[Troyhoo]

Hello, I have a GE ECM motor in a blower I wish to use as a shop/yard fan. It has a elaborate circuit and DC brushless motor. I was able to figure out that one must jump the 1 and 2 pins on the power connector to have it work properly on 120v with info I found on the net. I did get it working by providing the -voltage to the green and white wires. It blows perhaps a little stronger than a common 20" desktop fan, which is very impressive as it is only consuming 130mA to do it! The issue is that, I know having a 9.5" diameter x 10.5" width rotor, this is a far more capable blower than what it is doing now, I jumped the red and white wires to provide the same - voltage to activate full speed, but there no response at all, even left jumped for more than 10 minutes to be sure its not a delay issue. I wish to make this blower run at full power, or if possible perhaps use a potentiometer to control the speed. Does anyone know how to do this? Preferably without intense equipment like eprom burners I don't have. There must be some way to make the circuit run at max output I hope. Thanks, Troy

[hvac1000]

Hello, I have a GE ECM motor in a blower I wish to use as a shop/yard fan. It has a elaborate circuit and DC brushless motor. I was able to figure out that one must jump the 1 and 2 pins on the power connector to have it work properly on 120v with info I found on the net. I did get it working by providing the -voltage to the green and white wires. it blows perhaps a little stronger than a common 20" desktop fan, which is very impressive as it is only consuming 130mA to do it! The issue is that, I know having a 9.5" diameter x 10.5" width rotor, this is a far more capable blower than what it is doing now, I jumped the red and white wires to provide the same - voltage to activate full speed, but there no response at all, even left jumped for more than 10 minutes to be sure its not a delay issue. I wish to make this blower run at full power, or if possible perhaps use a potentiometer to control the speed. Does anyone know how to do this? Preferably without intense equipment like eprom burners I dont have. There must be some way to make the circuit run at max output I hope. Thanks, Troy

Troy. What you are trying to do was never the intention of the manufacturer of that motor. That motor is designed to have an exacting amount of back pressure on it at all times. Running at a very low speed as you are doing now is the only reason it has not been damaged.

These variable speed DC motors are designed to run in a restricted duct system and when run at high speed in free air as you want to do will quickly fry the electric controls in the motor end bell. In fact these variable speed motors present some problems when hooked to a duct system which keeps some back pressure on the air movement as I am sure you have already read about if you have done your research. In fact if you have done your research you have found that these type of systems should be setup using a manometer. That just goes to show you how sensitive they are.

The best system for air movement in a free air setup is a good old belt drive blower system from the older style furnaces and the next choice would be a standard 3 or 4 speed motor direct drive blower as now used in standard furnaces. You can make a blanker plate to partially close off the intake side of the blower to regulate over run.

A variable speed motor setup is designed to maintain a measured CFM no matter what the static pressure is. When used in free air there is NO static pressure for the motor to work against and that is where the problems start for a setup like you want to do. I am sure it is possible to do what you want to do but far to time consuming and expensive if equipment is damaged during the experimental phase.

[Troyhoo]

Troy. What you are trying to do was never the intention of the manufacturer of that motor. That motor is designed to have an exacting amount of back pressure on it at all times. Running at a very low speed as you are doing now is the only reason it has not been damaged.

These variable speed DC motors are designed to run in a restricted duct system and when run at high speed in free air as you want to do will quickly fry the electric controls in the motor end bell. In fact these variable speed motors present some problems when hooked to a duct system which keeps some back pressure on the air movement as I am sure you have already read about if you have done your research. In fact if you have done your research you have found that these type of systems should be setup using a manometer. That just goes to show you how sensitive they are.

The best system for air movement in a free air setup is a good old belt drive blower system from the older style furnaces and the next choice would be a standard 3 or 4 speed motor direct drive blower as now used in standard furnaces. You can make a blanker plate to partially close off the intake side of the blower to regulate over run.

A variable speed motor setup is designed to maintain a measured CFM no matter what the static pressure is. When used in free air there is NO static pressure for the motor to work against and that is where the problems start for a setup like you want to do. I am sure it is possible to do what you want to do but far to time consuming and expensive if equipment is damaged during the experimental phase.

Hello Hvac1000,
Thanks for you're your reply, you just confirmed my theory after playing more with it last night after posting my question. I noticed how unlike standard blowers that consume less current when the passage is blocked and it speeds up due to less still air being drawn in, this blower actually increased from 130mA to 1.5A in an effort to maintain the same torque on the wheel, and was really moving, seemingly far beyond the 1050 rpm stated on the motor. I did also notice it produced greater pressure then my other blower, and is able to maintain greater flow through a small duct then another blower I have about the same size with a typical capacitor motor.
I understand your caution about circuit over load attempting to run higher speeds against free air flow, however I can't help but think it can be safely set to run continuously at the 7 amps, as it has this stated on the motor label if there is airflow over the motor.
Since it is so much more effective with pressure I am considering a different application to cool 8 ducted battery packs for my Ridgid power tools, I made a higher flow charger for them with another blower, and although better then the stock units, this blower was able to force much more air though a pack in my test last night, and didn't use more current to do it at 1.5A. But its bulkier, and I really need a army of these blowers to keep working in this heat we are having here.

Is there a way to get it to run at about 6.5A without restricting the air flow? I am considering a nozzle like structure, but would prefer wider air movement so I don't have to redirect it as often.
I have a similar , but much smaller motor in a ducted fan designed to propel model jet aircraft, it has a similar circuit that is far less heat sunk, and is able to maintain 45A with no air flow over it, into this tiny little motor! Impressively this little 2.5" fan moves as much air as a one of these hvac blowers with the standard motor! But its extremely loud of course, and costly to make such high amperage power supplies for them.

I don't doubt the circuit could be damaged as you stated if set to the maximum output capability,which if anything like this other motor is likely far greater than the 7A the circuit can maintain in a full duty cycle situation, but I sure am hoping there is a way to set to up the speed in free air to just below the 7amps that is stated on the label can be ran continuously in a air over condition?

These motors are most fascinating I and would sure like to know more about making them work with a simple turn the dial for the speed you want application. Even the hobby fan I mentioned earlier, there are no circuits available for them that just have a simple speed and direction selection, all of them require a modulated signal to control as they can't seem to fathom that maybe someone might like these motors for non radio controlled application. I likely one day will try to make a circuit myself, but I just don't have time to spend on it at this point in my life.

Thanks again for the info, and also for any additional info on adjusting the output of this motor. There must be a setting for larger duct systems that need more flow to maintain the set pressure, right?

Also I am a little braver cause if I do burn some mosfets I would have no trouble repairing it. :) Though I agree I its best to avoid having to.
I definitely would appreciate any info you can offer.

Thanks again,
Troy

[NorthernHeat]

You are applying 24 volts to the low voltage pins correct? Depending what pins you apply it to the motor will run the program for that input and run the appropriate program.

A true ecm motor is a constant CFM motor, Meaning the motor uses the torque and rpm to move a constant, lets just say, 800 cfm on pin 1 and 1000 cfm on pin 2. Now if that is an x-13 ecm motor it is a constant torque motor and not quite as smart.

It would be very difficult to reprogram the motor since manufacturers have the means and their own proprietary software which they use. Also there are 2 sizes of ecm's 1/2 hp and 1 hp varieties

When you increase the static pressure on these motors the amp draw and rpm does adjust itself, but it is still moving the same cfm. The more work it has to do the more power it consumes.

Newer ecm motors since we are on generation 3 or 4 have an rpm limiter on them, they found out years ago with out this limiter they would try and spin themselves to death.

It is basically a computer running a 3 phase, brush-less, direct current motor. 2 phases are always energized and the back voltage on the 3rd un-uses phase gives the computer info on power, rpm and torque and all this happens in nano seconds.

Hopes this is a bit of a help.

[hvac1000]

You are applying 24 volts to the low voltage pins correct? Depending what pins you apply it to the motor will run the program for that input and run the appropriate program.

A true ecm motor is a constant CFM motor, Meaning the motor uses the torque and rpm to move a constant, lets just say, 800 cfm on pin 1 and 1000 cfm on pin 2. Now if that is an x-13 ecm motor it is a constant torque motor and not quite as smart.

It would be very difficult to reprogram the motor since manufacturers have the means and their own proprietary software which they use. Also there are 2 sizes of ecm's 1/2 hp and 1 hp varieties

When you increase the static pressure on these motors the amp draw and rpm does adjust itself, but it is still moving the same cfm. The more work it has to do the more power it consumes.

Newer ecm motors since we are on generation 3 or 4 have an rpm limiter on them, they found out years ago with out this limiter they would try and spin them selves to death.

It is basically a computer running a 3 phase, brush-less, direct current motor. 2 phases are always energized and the back voltage on the 3rd un-uses phase gives the computer info on power, rpm and torque and all this happens in nano seconds.

Hopes this is a bit of a help.

Well said NorthernHeat!!

[Troyhoo]

Well said NorthernHeat!!

Hello NorthernHeat, thank you also for you reply, I actually an using a 18v tool battery for my control supply as it was most convenient till I determine what I can do with this, I did however hook it with a 9.6 to give me 28v and the motor responded no differently. This is a GE 1/2hp motor, I don't believe its one of the x-13 units you mentioned, it is able to discern between resistance I apply to the shaft directly and un-restricting the airflow and responds differently. If I understand you correctly applying the -24v to specific pins determines the amount cfm it will try to move?

The motor I have uses the connector seen on page 3 of this website pdf document. http://documents.gotoevo.com/ECM%20S...0Procedure.pdf
I don't actually have the connector, after a conversation with my friend about another blower I set up be easily redirected and used the way I hope to use this one, he pulled this blower out of equipment being thrown away for me, when he found it there were no harnesses on it at all. Later when we discovered it was an advanced design and could not be wired as I was accustomed to, it was too late to go back for the other components that had been collected already. The schematic that is usually so helpful is present on the blower, but very weathered and unreadable, which strikes me as very odd since the blower is in like new condition, its not even dirty at all. I can stick wires into the connector to test purposes, but have been soldering wires directly to the board once deemed needed. Can you tell me which pins are safe to apply the -24v to change the cfm mode? I hate to start poking blindly at it and burn an unavailable part out. Thanks you for the info. I appreciate any information on this I can use to help me get the most out of this unit, I look at it and have no doubt this is most capable unit I have if I can get it set up right. Thanks, again , and have a great one. Troy