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    bwechner's Avatar
    bwechner Posts: 5, Reputation: 1
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    #1

    Jun 27, 2009, 02:39 AM
    Ancient Sunbeam Mixmaster only runs at full speed (speed control not fuctional)
    I wonder what's wrong? It's a wonderful antique. Looks not too different to this:

    Sunbeam Mixmaster Stand Mixer : Target

    It has a variable speed control. All of a sudden it no longer responds to the speed dial but runs top speed constantly.

    What is wrong and how might I go about fixing it? I can open it up, check bits and pieces even make changes am quite adept, but not particularly savvy on diagnosing electrical failures like this on my own either... and a bit puzzled about which part to suspect and whether I can repair it at all.

    Any tips would be appreciated.
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
     
    #2

    Jun 27, 2009, 03:28 PM
    More than likely the variable speed switch or the variable speed circuit has a problem. Old mixers are very hard to find parts for.
    bwechner's Avatar
    bwechner Posts: 5, Reputation: 1
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    #3

    Jun 29, 2009, 04:34 AM
    Quote Originally Posted by hvac1000 View Post
    More than likely the variable speed switch or the variable speed circuit has a problem. Old mixers are very hard to find parts for.
    I expect parts to be either near or actually impossible to find and even if findable very probably hard to justify buying given the unit itself is so old (and I'm not doing it up a s a retro or antique thing to on-sell, it's just genuinely old and hence I inherited it). Not sure of the vintage, and ironically the URL above shows me that they still make them in this style. Mine though is pretty sold meta and bakelite suggesting mid 70's at the latest to my mind but I'm no pro on the heritage of mixmasters and could be very wrong.

    Inside is a simple POT to control the speed so it's probably a DC or universal motor, and there is a large capacitor and another element looking similar but pained by some previous explorer methinks so I can't be sure it too is a capacitor. My best guess is one of these failed.

    My quest is to understand how to diagnose this and what kind of motor it is and what role these elements play in speed control or otherwise. The POT seems to work, that is I can measure radical variation in resistance across it as I effectively turn the speed control dial (which translates rotational to linear motion). I can't be sure they're the right resistances, lacking a spec, and can't rule out a POT failure, but it seems hugely unlikely as the common failure modes would be an open or closed circuit not a nice varying resistance different to that originally intended.

    In any case, that's the kind of experience I'm hoping to find on-line, but doubting I will. You never know, some really savvy folk are out there sometimes, but then again old mixmasters is pretty esoteric stuff...
    theman1956's Avatar
    theman1956 Posts: 1, Reputation: 1
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    #4

    Oct 12, 2009, 04:52 PM
    The govenor capacitor is shot. Google in Sunbeam motor govenor capacitor.
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #5

    Oct 12, 2009, 05:12 PM

    Unless it's one of these: Phil's Appliance Science - Restoration ,Sales & Service of Vintage Mixers and Small Appliances

    They used a big resistor which heated up and moved a bi-metalic contact. Resistor bad, contacts won't open. Contacts could have welded together, again high speed.

    Look for a model #. If the head detaches, it should be under there.

    The button in the middle of the dial prys off gently. Then turn it on it's face and remove the screw. Remove the dial. Turn upside down and a small part will drop out. It's used to adjust the speed range. There is a small hole and a rectangular slot that it drops into when putting it back together.
    Notamilgramman's Avatar
    Notamilgramman Posts: 2, Reputation: 1
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    #6

    Dec 10, 2009, 10:40 AM
    The Sunbeam Mixmaster mixers, Models 1-12 (produced c. 1935-1967), use a Flyweight Governor for speed control. Over these years two basic configurations of this governor were used, one from about 1935-1950 (Models 1-9) and the other from 1950-1967 (Models 10-12). Electrically they are identical so an explanation as to how one variety works electrically will suffice well for the other. There is a significant difference in the mechanical layout between the two iterations. The earlier design had the governor points located on a rotating part that also carried the governor flyweights. It used a pair of slip rings and brushes in addition to the usual armature commutator and commutator brushes, for a total of 4 carbon brushes. The later design used a fixed mounting for the governor points and eliminated the slip rings and their brushes. Although constructed differently, the basic physical operating principle is exactly the same. When discussing mechanics in detail, the construction of the newer 1950-1967 Model 10-12 design will be the basis.

    Because the speed control electrical section uses a power resistor many misunderstand the speed regulation of the Mixmaster to be accomplished by the classical method of inserting, and keeping in place, resistance in series with a motor to reduce the current through it, or, expressed another way, to reduce the potential across it, and thereby limit the motor's speed. While many motors of the Sunbeam and other types and have been regulated this way (variable speed drills, sewing machine motors, car ventilation blowers, etc.), this is not why Sunbeam uses the resistor. Neither does the Mixmaster have a variable resistor (aka Rheostat). It is understandable how ones familiar with electrical circuits come to a wrong conclusion about the resistor's function. But examination of the parts underneath the control knob, or of a Sunbeam schematic, reveals how the Mixmaster speed control really works. It is hoped the following explanation will help those interested in understanding how this mechanism, from times gone, does actually work, and, based on that understanding, know how to troubleshoot it.


    To begin with, the Sunbeam Mixmaster governor is a true speed (RPM) control, of the “flyweight” variety which operates in principle like governors used for electrical power generators and, formerly, mechanical car speed controls (i.e. Chrysler Auto-Pilot). Sunbeam advertising for the Mixmaster often used the phrase 'full power at every speed' to describe the benefit of this real speed control that formed the basis of the “Sunbeam Automatic Mixmaster”. Unquestionably superior to, and more costly than, other common methods of Universal Motor control, including part winding, series resistance, tapped transformers and moving brushes, the Sunbeam's motor power is, indeed, automatically adjusted to maintain the speed set on Mix-Finder knob. Sunbeam service literature states Speed 1 should yield 230-260 beater RPM and Speed 10 (or 12) should yield 710-865 RPM. Of course, if the load at any time exceeds the motor's maximum capability the motor will run slower than the set speed, but at the full power available, as the best the speed control can do at this condition is put the motor continuously “across the line” (this will be explained).


    The overall electrical arrangement is that the mixer motor, itself a Series-Wound motor (aka Universal motor, AC/DC motor), is in series with the electrical section of the governor, meaning the motor current must always pass through it also. The governor also has a mechanical section. Both sections are described below.

    Electrical Section

    Consists mainly of 3 components. All in electrical parallel with each other, meaning the current may pass through any one, any two or all three of these components. This parallel arrangement is not to be confused with the fact that, as a whole, this entire circuit it is in electrical series with the mixer motor.

    1) Power Resistor. Nominal Resistance: 150-200 Ohms. Continuous Power Capacity: 10 Watts.

    2) Points. A set of spring loaded contact points. There is another set of contact points that are just the OFF/ON switch.

    3) Capacitor. Nominal Capacitance: .08 μF. Voltage Rating: 160 Volts.

    Mechanical Section


    1) Flyweights and Linkage. Mounted to the motor armature (the spinning part) and used to generate a force, through centripetal acceleration required to keep the weights' moving in a circle, which is transmitted by linkage to the Governor Points and tends to open the point set by axially moving one of these spring loaded points away from the other. Specifically, by moving the “rear” point (connected mechanically to the Flyweights) away from the “front” point (connected mechanically to Speed Dial). The faster the motor armature rotates the greater the force generated.


    2) Speed Dial and Linkage. Via a small, adjustable length rod, the Speed Dial rotational position (speed setting) sets a fixed limit to the position where the “front” point of the Governor may move axially. The lower a Speed Dial setting, the less the distance the spring loaded “front” point may move rearward, under its spring force, in its attempt to follow and stay in contact with the “rear” point; and vice versa.

    Note that the Points are part of the Electrical and Mechanical Sections. The contact points proper are each bonded to an electrical current carrying, thin, metal stamping which is slightly bent in the assembly (the complete assembly has the OFF/ON Main Switch contacts, the Points being discussed and the holders for the Power Resistor and Capacitor) to provide the forces discussed above-there are no typical wire wound springs in the Sunbeam speed control.


    With the above general description in mind the following can help to complete the picture as to exactly how the speed regulator functions when operating.

    Whenever the Points are closed the motor is directly connected to the power supply and the mixer will run as fast as it can with the load placed upon it.

    With closed points it is as if the power cord was directly connected to the motor (aka, the motor is “across the line”) and the mixer was a single (high) speed machine. This is, in fact, exactly how older single speed blenders, vacuum cleaners and circular saws, which use the same type Series-Wound motor as the Mixmaster, operate.

    Whenever the Points are open the Power Resistor is electrically placed in series with the motor.

    More precisely, “bypassing” or “shunting” of the Power Resistor is removed when the Points are open. When the Points are closed the vast majority of motor current goes through them because their resistance is very much lower than the Power Resistor and, therefore, the resistor is effectively bypassed. Summing up, when the points are open the only path for motor current is through the Power Resistor-the other path through the points is broken and the current flow through the Capacitor is absolutely negligible (about 4 mA).

    I have measured the resistance of Model 10 and 11 Mixmaster motors to be right about 20 Ohms and this should hold for all 120 Watt models which is all except some for Model 12's. Several of the Power Resistors I have checked are about 180 Ohms. Thus, and this is important, when the Points are open total circuit resistance is about 10 times as great as when the points are closed. Therefore, with the Points open motor current will then be about 1/10 as much as with points closed and motor power, which is proportional to the square of motor current, roughly 1/100 of maximum. This is a useless power level as the mixer barely turns with no load. Correspondingly, when the resistor is in the circuit it dissipates about 65 Watts at 0 RPM-as opposed to about 7 Watts in the motor windings, with DC applied, and not much less than 65 Watts at the speed the motor revolves at under this condition. (As the motor armature begins to turn less current flows through the motor and, therefore, the resistor. But because the motor turns so slow it is very nearly the same as 0 RPM current levels). At 65 Watts the resistor will “fry” in no time. The Points are never supposed to dwell open for any length of time, not even when the motor is at 0 RPM, and the fault condition where they do stay open is addressed in troubleshooting.

    Clearly, the 10 Watt Power Resistor was not designed for motor current to be continually flowing through it. But placing resistance in series with the motor is exactly how many motors have been made to run at slower speeds. This, again, explains the confusion about what this resistor does. What the resistor does do is explained later.


    The speed regulation of the mixer is achieved by the Governor Points being rapidly opened and closed.

    The speed control is simply very quickly switching between full power and 1/100 power (at the particular RPM) or effectively turning the motor off and on quickly to maintain a certain speed. Basically, the cyclical switching is the result of an unsteady equilibrium between two forces: the force produced by the flyweights and the force produced by the distortion of one of the thin metal stampings described earlier-the one the rear point is mounted to. If not too heavily loaded, armature rotation will produce enough force, via the flyweights, to push the rear point, which is tending to be held against the front point by spring generated force, away from the front point when the set speed is slightly exceeded. When the points open the armature rapidly decelerates because, essentially, the power to the motor is being cut off by insertion of the Power Resistor into the circuit. Very quickly the spring generated force overcomes the flyweight generated force enough to push the points closed again whereupon the armature accelerates and the cycle repeats.

    If you try this method of speed control with a normal switch it will burn out real fast because of sparking and its attendant heat. The sparking occurs due to the current not wanting to stop flowing, like water-hammer in a pipe. Sparking is especially bad at low RPM when more current flows through the motor due to its lower counter-voltage generation. Even the Points, made from special material, can only take limited sparking so…

    The Capacitor and Power Resistor work together to reduce sparking at the Speed Regulator Contact Points and give them a reasonable lifetime.

    In the explanation of the previous section it is reasonable to ask “why bother to use the Power Resistor if it supplies just 1% of the power that would be otherwise present-why not just 0%? In other words, when the points open why not just shut the current off completely instead of just reducing it by 90%.” Answer: You could. If you remove the resistor from the Mixmaster you may not notice a difference. But jerky operation at slow speed with light load and increased spark noise are often observed-same effect if the capacitor is removed-not sure which causes more negative results. The fact that the Mixmaster will speed-wise run exactly the same with or without the Power Resistor in place proves indisputably that the Power Resistor in the Mixmaster is in no way used for speed control. So why is it there?

    The reason for the Resistor and the Capacitor in the Electrical Section of the Governor is to prevent rapid the points from premature burn-up and no other reason. The Resistor and Capacitor work together as sort of an electrical shock absorber. When the points open the current doesn't have to completely stop because the Power Resistor provides a path and the Capacitor, which is also “bypassed” with the points closed can absorb much of the energy that would be dissipated in a much larger spark if were not present. If you remember when cars had “points and condenser” in the ignition distributor, the condenser (another name for a capacitor) absorbed much of the spark that developed at the points when they opened to fire a spark plug-sometimes you couldn't run without it-so much energy was lost in the spark at the breaker points and was unrecoverable.


    When the Mixmaster is switched off the Capacitor still has line voltage across it.

    The Governor Points and Power Resistor are disconnected from the line when the Speed Dial is set to OFF but the Capacitor is not. This means that any time the mixer is plugged into an AC outlet there is a small current (about 4 mA) flowing through capacitor, and, because there is a non-zero power factor (about 10%) associated with real capacitors, a very small power dissipation takes place in the Capacitor (about 50 mW) and motor windings (0.2 mW), due to this current and a very, very small demand is placed on power line. So the Mixmaster perhaps would not qualify as an Energy Star device. Of course, if DC was used there would be essentially no current flow and no power taken from the line.

    I'm not sure why Sunbeam put the one capacitor leg beyond the Main Switch. Perhaps to absorb the spark energy from the Main Switch contacts opening when the mixer is shut off. At any rate this leads to a weirdness that will be discussed in troubleshooting.


    Troubleshooting

    This section is written for persons who have some mechanical inclination. If you come into possession of a classic Mixmaster consider a complete disassembly, inspection, cleaning, lubrication and adjustment essential; that is if you want to use it and not just flip-that-mixer on eBay. There is a great source for the official Sunbeam service procedures, which include a schematic and an exploded view of the mixer, from www.davesrepair.com. Dave has used and tested original resistors and capacitors, re-coated and tested resistors with a nicer appearance, and brand new capacitors that he makes which look and install just like the originals. He is working on new resistors. This should make the “adaptation” of modern components a thing of the past in servicing these machines.


    Mixer Does Not Run

    1. Plug mixer in.

    A. Motor Buzzes: Completely disassemble, inspect, repair, clean and lube the mixer or have someone who appreciates these machines, not just someone who knows how to, do so.

    B. Motor Does Not Buzz: Go to step 2.
    .
    2. Remove the Speed Dial.

    3. Locate two wires, one connected to either side of the Switch/Point Assembly, near the bottom of it. These two wires go into the motor case together at the center bottom of the end plate that the regulator is mounted on. Remove both wires from their terminals.

    4. Place wire eyelets together and put one screw through the eyelets to hold them together or use any other means that holds the wire eyelets together and does not allow electrical conduction to anything else.

    5. Plug mixer in.

    A. Runs: Bad Switch/Point Assembly, replace it.

    B. Doesn't Run: Problem with cord, brushes or motor windings. Use test light or meter to trace down or send in for repair.


    Mixer Will Not Turn Off, Runs Whenever Plugged In

    1. Remove the Speed Dial.

    2. Remove Capacitor (the lower cylinder) and Resistor (upper cylinder) from their spring mounts.

    3. Hold Speed Knob in position by hand, pressing forward with enough force to hold knob fully forward when in the OFF position.

    4. Plug mixer in.

    A. Runs: Unplug. Bad Switch/Point Assembly or Speed Dial-replace as needed.

    B. Doesn't Run: Unplug. Go to step 5.

    5. Re-install resistor.

    6. Repeat step 3.

    7. Plug mixer in.

    A. Runs: Unplug. Bad resistor-replace.

    B. Doesn't Run: Unplug. Bad Capacitor-replace.

    Remember that the Capacitor still furnishes a path for a small current to go through the motor even with the Main Switch off. It should only allow a very small current. But when it shorts out it becomes an easy path for current and the motor runs whenever the mixer is just plugged in-regardless of the Speed Dial setting.

    Mixer Only Runs At Full Speed, But Does Turn OFF.

    1. Remove the Speed Dial.

    2. Is there a small rod protruding from a round hole to the right of and near to the shaft where the Speed Knob mounts?

    A. No: Replace rod.

    B. Yes: Go to step 3.

    3. Push rod in with screwdriver.

    4. Plug in mixer.

    A. Runs Slow: Unplug. Adjust Rod, make sure Speed Dial retaining parts (screw, flat washer, and wave washer) are all present, inspect Speed Dial tab, used for Main Switch operation, for damage, check the speed “ramp” where the round end of the adjustable rod rides. Replace parts as needed.

    B. Runs Fast: Unplug. Go to step 5.

    5. Remove Resistor.

    6. Push rod in with screwdriver.

    7. Plug in.

    A. Runs Fast: Fused Governor Points-replace Switch/Points assembly.

    B. Does Not Run: Shorted Resistor [never seen before but possible]-replace.


    Resistor Check

    NOTE: The Power Resistor in the Mixmaster can get to look real bad but still be perfectly good. Visual appearance therefore is a poor indicator of actual resistor condition. Indeed, a perfect looking unit may be open circuit.

    1. Remove the Speed Dial.

    2. Push adjustable rod in with screwdriver.

    3. Plug in mixer. Do not run under this condition for more than a few seconds.

    A. Mixer runs very slow. Unplug. Resistor good.

    B. Mixer doesn't run: Unplug. Go to step 4.

    4. Remove resistor.

    5. Thoroughly clean resistor ends with abrasive. Be careful not to damage the delicate resistance wire to end conductor connection.

    6. Install Resistor and repeat step 3. If still a no run condition replace resistor.


    Capacitor Check

    NOTE: If the capacitor is shorted the mixer will operate no matter what the Speed Dial position. See Mixer Will Not Turn Off, Runs Whenever Plugged In for a definitive root cause determination for this problem. The equipment needed to accurately determine capacitor condition is not usually available to DIY's. A capacitor passing the checks described below indicates an acceptable capacitor.


    1. You have a DMM or Multimeter?

    A. Yes: Go to step 2.

    B. No: Perform Resistor Check then check amount of sparking as discussed in Excessive Sparking/Motor Jerks.

    2. Set the meter to read Ohms in the highest range. NOTE: This gives the highest voltage between the leads (at least for some meters) and the most sensitivity to current flow. The meter is actually measuring current to obtain a resistance reading.

    3. Remove capacitor.

    4. While observing meter, place capacitor across the leads for a few seconds then quickly reverse lead positions.

    A. Meter reading spikes down from infinite to a value and then back to infinite, then upon lead reversal spikes farther away from infinite the back to infinite: Capacitor can be considered good.

    B. Meter reading remains infinite or very little discrimination between initial meter deflection and deflection upon lead reversal: Capacitor Bad-replace. Www.davesrepair.com

    NOTE: You should observe a momentary spike down from infinite resistance to some high value of resistance then back to infinite. This is capacitor charging to the potential of the meter's resistance measuring circuit. Upon lead reversal you should observe an even greater, longer lasting deflection from infinite to a value then back to infinite. This greater initially greater deflection from infinite is a result of higher current flow through meter caused by the capacitor's potential, obtained by charging, being added to the meter's potential, instead of being in opposition to it as was the case during charging. By alternately switching the meter leads the basic condition of a capacitor across an AC line is very roughly duplicated. The important thing is to get some deflection upon initial charging and a greater deflection upon lead reversal as long as the meter is allowed to go back to infinite before the leads are reversed.



    Excessive Sparking/Motor Jerks

    I check for excessive sparking in a dark room with the mixer on Speed 3 after my eyes have acclimated to the dark. What you should see through the Speed Dial vent slots is a faint bluish-white, nearly constant light resulting from just a little sparking. The motor should have a pleasant hum and jerking, spark pop, or bright flashes of light should be present. All this sounds nebulously subjective I know, but in not much time you get to know how these machines should run.

    On Model 12 there is additional shielding of the contact points that should be removed before this test is done. Remove the Speed Dial, then remove the cardboard shielding and reassemble Speed Dial to mixer.

    There are several problems that could cause excessive sparking and/or motor jerking. First, check the Resistor and Capacitor. The resistor is easy to check even without a meter. The capacitor, though, cannot be accurately checked without a capacitance meter or an AC Milliammeter.

    If the resistor and capacitor checked good and there still is too much sparking I suggest you first replace the capacitor with a known good one: www.davesrepair.com. If the problem still exists, the motor armature may have shorted section(s). A test light or multimeter and possibly a “growler” and knowledge are needed to find out the problem.

    Again though, the resistor and/or capacitor are the likely problem. But not long ago I ran across a Model 10 with fried points-completely burned away. With a know good resistor and capacitor along with a good points assembly the motor still jerked and the points still sparked. It turned out the armature had some kind of short as the certain commutator segments were badly burned at the edges. That Model 10 became a parts donor.

    Speed Change Limited-Does Not Appear to Have Full Range of Speeds

    1. Plug in.

    2. Set to Speed Dial to highest speed.

    3. While the mixer is running lubricate it at all lube locations.

    4. Let run for 1 hour then check range.

    A. Range Good: Keep lubricated and run regularly.

    B. Range Bad: Go to step 5.

    5. Perform complete CLA and recheck speed range.

    A. Range Good: Done.

    B. Range Bad: Go to step 6

    6. Plug In.

    7. Set Speed Dial to 1.

    8. Is beater speed a nice slow speed that allows for dry ingredients to be added to the mixer bowl without them being thrown out of the bowl?:

    A. Yes: Governor Flyweights, Linkage, Switch/Points Assembly may be at fault-send unit for repair if especially desirable model or use for parts.

    B. No: Go to step 9.

    9. Insert 1/16 Hex Wrench into small into small hole in rear of Speed Dial. NOTE: For Model 12 you have to remove the large rear cap on the Speed Dial.

    10. Turn wrench to give 230-260 beater RPM which is a nice slow speed that allows for dry ingredients to be added to mixer bowl without being thrown everywhere.

    11. Check High Speed. Beater RPM should be 710-865 (mixer runs fast). If range is still bad Governor Flyweights, Linkage, Switch/Points Assembly may be at fault-send unit for repair if especially desirable model or use for parts.

    Shock From Motor Case

    1. With a meter or test light trace the ground problem-most likely it is motor cord related.

    NOTE: The Mixmaster is an ungrounded machine and you should run it on a GFI circuit. There is one particular thing that may cause this in Models 11 and earlier. Sunbeam used another capacitor in the “belly” of the motor case, evidently to suppress radio/TV interference-remember when running a vacuum cleaner caused the TV to scramble? This capacitor can short line to motor case or line to neutral-either requiring a double fault of this 3-way capacitor. Model 12 no longer used this capacitor although electrically identical to earlier models. Because the motor case of Mixmaster is not grounded, if this capacitor were to short to the motor case line potential would exist between the motor case and ground.
    Notamilgramman's Avatar
    Notamilgramman Posts: 2, Reputation: 1
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    #7

    Dec 12, 2009, 06:02 PM
    I forgot to included one condition of bad operation in my post of December 10, 2009. It is below.

    Mixer Only Runs At Very Slow Speed

    NOTE: This condition is due to the Governor Points being burned out or failing to close and therefore the Power Resistor is always in the circuit. If the Mixmaster is run under this condition for any length of time the Power Resistor will burn out and then the condition will become Mixer Does Not Run-No Motor Buzz.

    1. Remove Speed Dial.

    2. Inspect mechanism for something physically holding the Governor Points apart (i.e. Jammed Control Rod, debris, etc.)

    3. A. Physical Jam Found: Clear jam and test Power Resistor.

    B. Physical Jam Not Found: Governor Points Open (burned up). Replace Switch/Points assembly and test Power Resistor.
    NelsonEZY's Avatar
    NelsonEZY Posts: 1, Reputation: 1
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    #8

    Oct 27, 2012, 08:37 AM
    Check with NelsonEZY.com to see if they have the used vintage parts available.
    Terry Kay's Avatar
    Terry Kay Posts: 6, Reputation: 1
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    #9

    Mar 6, 2013, 10:10 AM
    Very thorough and complete information on the govorned speed process.
    Now, tell me plain english if you would, why the mixer would fluctuate at lower speeds, and run wide open at any other setting greater than #4.
    The contacts have what looks like a burr in the edge of them, and I'm thinking that this is creating the on -off fluctaion of the lower speeds.

    What are the actual ohm values of the speed capacitor, & the other red porcelin coil or capaicitor on the top portion of the speed control?
    In real time?
    The machine is perfect other than this burr in the saddle.
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #10

    Mar 6, 2013, 10:40 AM
    The basic values were stated in the article. Capacitors have capacitance. If out of circuit, they measure shorted with an ohmmeter, they are bad. A capacitance meter is used to check a capacitor.

    The bur can carefully be removed with an emory paper or a nail board file.

    It' entirely possible that the contacts are welding.

    What was missing in the description is that there is a speed control ADUSTMENT. Usuually when this is out of wack the speed control will generally act like your taking about. Erratic low speeds and stuck on high at a low number.

    I'd bet it's due to some metal fatigue in the springiness of the contacts.

    If I remember right, there is a small tiny piece of Bakelite attached to a rod. Don't loose it That rod can be removed and turned so it's length changes, thus adjusting the dial.

    I'd either guess that the contacts are too close, are meeting at an angle, a burr is causing th contacts to weld or the control just needs to be adjusted.
    Terry Kay's Avatar
    Terry Kay Posts: 6, Reputation: 1
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    #11

    Mar 6, 2013, 11:43 AM
    Why am I having problems responding?
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #12

    Mar 6, 2013, 12:08 PM
    Only a few posts. Your probably one moderation. Posts won't show up immediately.
    Terry Kay's Avatar
    Terry Kay Posts: 6, Reputation: 1
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    #13

    Mar 6, 2013, 02:19 PM
    Ancient Sunbeam Mixmaster only runs at full (speed contol not functional)
    What I had mentioned was that the points are not laying exactly flat on one another, they are staggered a little due to the burr on the inside contact.

    I didn't see any Bakelite insulator on the governor shaft, if this is where it goes.

    I cleaned the contacts with a flex stone, and then blew them clean with CRC contact cleaner.

    It runs a little smother at low speeds, but still kind of hesitates at low speeds.
    It isn't even a hesitation,it's an on-off thing in the low speeds-- it doesn't run smooth till I get up around 4th-5th speed, than it's OK.
    But I can't tell the difference between 5th speed & 10th.
    On the way back down either--it doesn't slow down till I get to 4th or lower.
    Terry Kay's Avatar
    Terry Kay Posts: 6, Reputation: 1
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    #14

    Mar 6, 2013, 02:24 PM
    Let me ask this question regarding the contacts;
    Is my only resolve going to be buying a used machine & hoping that it's all good & operational , and then just swap the point plate?
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #15

    Mar 6, 2013, 06:18 PM
    Terry:

    Part #47 is the part that can be expanded or contracted thus adjusting the speed dial.

    Make sure the contacts hit square.

    Parts are nearly impossible to find.
    Attached Images
  1. File Type: pdf Parts Breakdown.pdf (17.5 KB, 444 views)
  2. Terry Kay's Avatar
    Terry Kay Posts: 6, Reputation: 1
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    #16

    Mar 6, 2013, 11:13 PM
    I think that part # 47 looks like a roll pin with the end of it that mounts into the point plate holder is half the OD and flattened on that end so it's a half mooned.
    It does fit pretty loose in the hole in the point plate, the black bakelite arm seems do be doing the supporting of it.

    Your saying I should open up the roll pin on the control knob side a little ?
    Not sure what that would do--but if that's part of the solution I'll give it a shot.

    Thanks Much,

    Terry
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
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    #17

    Mar 7, 2013, 12:40 AM
    That "pin" is actually is a screw and nut combination. It will lengthen and shorten.

    Take it completely out and try to find the seam and try to turn it.

    Think, something like this: Binder - Screw Post (Chicago Screws) 3/8" Nickel Solid Brass 100pack

    Just be careful taking things apart. Have a large clean surface in case you drop anything.
    Terry Kay's Avatar
    Terry Kay Posts: 6, Reputation: 1
    New Member
     
    #18

    Mar 7, 2013, 07:23 AM
    I'll take a look at it today.
    It does have a shoulder or groove cut into it about a 16th above where the pin sits into the point plate.
    I thought it was odd the there was nothing retaining it into the plate, it just sits in the half mooned hole--and comes up in through the bakelite arm that supports it, and then rides on the ramp on the backside of the speed control knob--

    I'll have to get a better pair of goggles to zero in on this adjustable phenomina.

    Thanks Much for the help--

    Terry
    whatupdown's Avatar
    whatupdown Posts: 1, Reputation: 1
    New Member
     
    #19

    Sep 11, 2013, 12:38 PM
    The cap is shorted, size of a AA battery, pop it out and it will work close to norm. It is held in by tension.
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member
     
    #20

    Sep 11, 2013, 07:35 PM
    Last I checked that thing is a resistor. It's not really held in by tension, but rather the spinning of the rotor forces it toward the back contact. An inertial speed control.

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