I have a small "silent" air compressor which utilises a freezer motor/compressor unit. I therefore presume that the wiring to the compressor should be the same (or nearly the same) as a normal fridge/freezer or air conditioner compressor.

I bought this compressor as a faulty unit, with a damaged starter relay and disconnected (and incomplete) wiring. After purchase I verified that the motor circuits were OK with an Ohm meter. I then jury-rigged wiring using the wires that were present and the compressr started and ran correctly.

I then obtained a new starter relay, disconnected the broken one and tried to wire-in the new one (of a slighty different design, but obtained from the compressor manufactirer as a direct replacement). However, I must have messed up the wiring as the compressor will not now run. Can anyone tell me how the unit should be wired?

These are the components;
1/ The compressor has standard-type fridge/freezer connectors (3 pins in a triangle formation) and I have identified the Common, Run and Start pins.
2/ Live, neutral and earth wires run from the pressure switch to a terminal block. All wiring to the terminal block is present.
3/ The live terminal from the terminal block is connected to a thermal cut-out, which in turn has a black wire running from it which terminates in a pin-type connector to attach to the compressor motor.
4/ A "motor starter relay" (this is how the compressor's manufactirer describes it). This has two connections and an exposed coil (i.e. there isn't the usual square-type cover over the coil, but the coil has a transparent plastic insulator sprayed onto it). These two connections have screws for (presumably) attaching ring-type terminals. There is also a blue wire running from the relay to the neutral connection on the terminal block. When testing I found that there is continuity between one of the screw connectors and the blue wire, and no continuity with the other screw connector, so the new relay's circuitry seems to be OK - at least when at rest.
5/ A cylindrical object (which I assume contains a capacitor) about 5 inches long and 2 inches in diameter which has "Motorstart" (amongst other non-English wording) printed on it. Two wires run from this unit, each terminating in a ring connector.

There is no other wiring present; I presume that I am missing at least two link wires since the wiring that I have has only one connector capable of connecting to the three pin connectors on the compressor. (I have terminal connectors available with which to fabricate any missing link wires.)

I have a digital multi-meter available if this is needed to identify any wires.

Can anyone advise how this compressor should be connected?

Thanks.

Part numbers?

Brand names?

Thanks for your reply.

I am not sure how much this information will help as this item is sold as a compressor so I have included all the information I have or can find;


The compressor is a Clarke Shhh 3/9. The model number is shown on the data plate as 2320770.

Clarke assign the part number MF7535 to the starter relay. On the relay itself the initials MIRP are moulded into the body, and the numbers 0030-36 714 and 2-277-011 are stamped.

The cylindrical object, which I assume contains a capacitor, has the following information stamped onto it;
Motorstart
DUCATI energis
ANLASSKONDENSATOR – Elytrauh
12.80.4.102 2.252.031
59 uF +/- 10% e
330V ~ AB 1.7% ED
SD 3 min. JUF
330V ~ 3/1.7
-10 / 55
50-60Hz
S22/02 (I guess this is the manufacturer's part number)

One of the wires from the cylindrical capacitor is coloured brown, the other blue.

Hope this helps.

Thanks.

Is this a air compressor? If so I have no information, I tried to look up Clark in the universal HVAC listing service and Clark is not listed. I guess it could be a product from another country but not from the USA.
Sorry

Yes, it is an air compressor. I thought I had indicated this in my first post but guess I didn't make it clear.

The machine is marketed in the UK. Sorry I didn't mention that; I obviously should have done so.

I realise that this is not an air compressor forum, but I couldn't find a more appropriate place to post my query. I had hoped that as the compressor utilises a freezer motor/compressor unit the components and connections might be universal and that someone here could give a general guide based on their knowledge in other areas.

I doubt that it will help, but if anyone is interested you can see the compressor in question by clicking here.

If anyone can offer any general advice regarding connections for such motor/compressor units involving a starter relay and (what I assume to be) a starter capacitor I would appreciate it.

Thanks.

These may be of help. It is a generic setup but may work for you.

I figured the unit was not from the USA but I am glad you confirmed.

Good luck and post back if the diagrams helped.

Attached Images

Comp1.pdf (179.2 KB, 263 views)

Excellent! Just what I was hoping for.

I will experiment and let you know the result.

Thanks for your help.

Hope you get it working.