So my overhead hoist is acting up. I have an 8 button pendant. Stop, on, up, down, left, right, forward and reverse. So the crane kept kicking off and had to hit the on button. It got bad over a months time where I had to hold the on button to control the crane. I thought the o/l relay was bad so I replaced that whole unit. Now nothing as far as movement goes but my contractors on my starter motors still operate. I put old unit back on and it works if I hold the on button. Reinstalled new one and just contractors again. I bought this the 15 years ago used. Has someone bypassed something or do I have a bad transormer?

 

 

I can fix it, but I'm not there.
No where near enough information to even begin to make a guess.
You may need to call in a Professional-Electrician.
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The contactor which activates when you push the on button is supposed to latch on and stay on until you push the off button. It's not doing that. Which is why you need to hold the on button down to get the hoist to do anything. Figure out why the on contactor is not latching on.

 

Check the contacts on the stop button. They will be normally closed. If they are intermittent or high resistance that will cause the problem. Also check the maintainer contact on the contactor. This will be in series with the contactor coil and stop button. In some cases one of the main contacts may be used to hold the conractor in once the start button is released. I agree with LowQcab that you have not provided enough information. Trace out the schematic of the control box and a picture so we can see the whole unit rather than just part of the caontactor. Is it single phase or three phase ?

Les.

 

 

I'll get some better pictures when I get to work. I appreciate you guys and ill do my best to provide better information

 

Check the contacts on the stop button. They will be normally closed. If they are intermittent or high resistance that will cause the problem. Also check the maintainer contact on the contactor. This will be in series with the contactor coil and stop button. In some cases one of the main contacts may be used to hold the conractor in once the start button is released. I agree with LowQcab that you have not provided enough information. Trace out the schematic of the control box and a picture so we can see the whole unit rather than just part of the caontactor. Is it single phase or three phase ?

Les.

Good call ill check that! It just doesn't make sense that I put a whole new unit on and the crane will not move with the on button held. I put the old one on and it does.

 

I suggest sticking with the old one for now. When you trace the schematic it will make fault finding easier.
Does the fault occur in both up and down directions ?

Les.

 

I suggest sticking with the old one for now. When you trace the schematic it will make fault finding easier.
Does the fault occur in both up and down directions ?

Les.

It faults the whole crane. The contractors to move the actually crane activate but no movement unless you hold the on button

 

It faults the whole crane. The contactors to move the actually crane activate but no movement unless you hold the on button

When I put the new motor starter on it does nothing

 

From the last pic the TS posted I can see it's 3 phase. But I'm pretty sure the control voltages are all single phase low voltage (24v or so). The wiring for a crane should be very straight forward. It's basically just switches and relays.

 

Re post #11. The fact that the contactors (I assume one for up and one for down.) stay latched in means my suggestions about the stop button contacts or maintainer contacts is wrong. Does the fault effect the left, right forward and reverse as well as the up down ? I am now guessing that there are three mechanically interlocked reversing contactors. (Each of these like two contactors linked together.) Are there any more contactors or relays ? Are there any relays in the pendent with the 8 buttons ? I am not clear how the ON button functions. I imagined you would press one of the 6 direction buttons and the crane would move in that direction until the stop button was pressed. (Or until it reached a limit switch.)

Les.

 

Re post #11. The fact that the contactors (I assume one for up and one for down.) stay latched in means my suggestions about the stop button contacts or maintainer contacts is wrong. Does the fault effect the left, right forward and reverse as well as the up down ? I am now guessing that there are three mechanically interlocked reversing contactors. (Each of these like two contactors linked together.) Are there any more contactors or relays ? Are there any relays in the pendent with the 8 buttons ? I am not clear how the ON button functions. I imagined you would press one of the 6 direction buttons and the crane would move in that direction until the stop button was pressed. (Or until it reached a limit switch.)

Les.

So it has the starter motor i posted picture
Then there is a transformer and another box with 2 starter contactors. The pendent does not have any relays. It works as each button moves directional until released. Never have to push stop

 

 

2 of these in the second box. If you hold the on button it activates either one of these. They control the forward and reverse of the crane. Still odd that I have tried 3 new motor starters and they will not do nothing but the old one will function if you hold on

 

I will get more pictures asap.

 

I am not sure what you mean when you say "motor starter". Could you explain that please? There is also the possibility that your OFF switch in the pendant is broken. That switch should be a Normally Closed switch and it may be broken in the open position. I could be wrong about this but it would not hurt to check the switch.