Hi there, I've an oldish Ac motor, 240v , 4kw from a car ramp. It was working until had a wiring issue. There are no safety cut out switches connected. The problem is with the motor wiring itself. There are 4 wires, no capacitor. Two wires are currently connected, unsure about how to connect the other 2. The motor tries to go, and will if give the motor a bit of help by hand by pushing the large pulley. It just doesn't want go by itself though trying. Here's a diagram from its casing. Wonder if 4 wires, a start circuit I need to connect, then a different circuit once it's got going? Any help appreciated please

 

Just to say, had it wired up a few years ago , working fine, knocked some wires then just left it and forgot how it goes now.

 

That is odd there is no capacitor.
Having to spin it to get it to revolve is a typical symptom of bad capacitor.
You will need to measure the various windings to find out the layout.

 

When you say that there are 4 wires do you mean 4 wires from the motor windings or 4 wies comming to the motor from the control gear. A picture of the motor connection box as it is now might be helpfull. I assume that there are 4 wires (plus a ground wire.) between the motor and control gear. In the control gear is there one contactor that pulls in for up and one that pulls in for down ? Can these contactors be operated manually (WITH THE POWER SUPPLY TO THE MACINE DISCONNECTED.) so the resitance testing can be done to identify to identify which pair have the polarity reversed between up and down ?
Edit. I have just seen Max's post . Mabe the capacitor is in with the rest of the control gear.

Les.

 

That is a 5HP motor, for that size, I would have expected a start and a run cap!

 

Thanks so much, I'll get a photo tomorrow but 4 wires from the motor not control gear. Infact it's a motor from something else that was adapted to fit the car ramp. Can't see a capacitor anywhere

 

From the connection diagram, it seems that each double pair of windings, start and run, are either in series pair or parallel paired.

 

I've got some pictures, this is the control panel the left switch is the power, the two right, down ( as in picture) for motor one way, switch both to up for motor other way

 

Switches

 

This is the motor, it's my father who installed it years ago, now forgot. Reckons a 3hp, says definitely no capacitor

 

And these are the wires, the two with yellow crimps on ( to the left) are now no longer connected, but were somewhere. The two that are connected seem to go into the motor windings, not to the actual bit in front with connections on

 

Looks all confusing

 

Switches

Looks like a bit of a mess, in general.
If that is 14g wire, it would seem undersized wiring?

 

Very unusual to see a split phase motor (no cap) over 1kw, the motors have very low starting torque.

 

And these are the wires, the two with yellow crimps on ( to the left) are now no longer connected, but were somewhere. The two that are connected seem to go into the motor windings, not to the actual bit in front with connections on

It's a bit of a puzzle! The two wires with crimps on are not the correct colour I don't think, just any old wire used I believe so guess must work out what they are by where are connected on the terminal? All the wires going to the terminal block from the motor windings are brown. Not helpful

 

Looks like a bit of a mess, in general.
If that is 14g wire, it would seem undersized wiring?

Yes perhaps, but it did work for a few years

 

I am assuming that that there is no control box with contactors. I am making a wild GUESS that one of the switches is an on / off switch and the other two control the direction and that only ONE of these two switches ia on at a time. One for forward and one for reverse. If both of these switche are on at the same time it blows the fuse. Is this guess correct ?
I can't display the pictures of the connection box large enough to see the connections.

Les.

 

I am assuming that that there is no control box with contactors. I am making a wild GUESS that one of the switches is an on / off switch and the other two control the direction and that only ONE of these two switches ia on at a time. One for forward and one for reverse. If both of these switche are on at the same time it blows the fuse. Is this guess correct ?

Les.

Hi Les, that's it. I'm not sure but think my father did put all on by mistake, but unsure if was a fuse to blow, just the main supply fuse. He took the 4 wires going to the motor apart now can't figure where they go. Thanks for everyone's replies, a clever bunch by the sounds of it

 

Yes, it should be set up with proper reversing contactors, but initially I would connect the power direct as shown on the plate and get it running first.

 

Yes, it should be set up with proper reversing contactors, but initially I would connect the power direct as shown on the plate and get it running first.

Thats what I'm not sure about, how to connect direct please? Yesterday I got some pedals and a control box for up and down. Hope to connect this up