Reversing contactor

[bozlite]

Good afternoon, everyone. Hope somebody might be able to help.

Below is a picture of what I have recently discovered is an Albright SW202 reversing contactor, which is supposed to operate my bow thruster. It seems to have failed, however.

I hope it's possible to see enough of the the wiring to make sense of it. The main input is attached to the stud at bottom left, this is linked to the stud above it by a copper strip. There's a connection on the upper stud (thin red wire) which terminates in the choc box (why?). The studs at the left rear of the unit (top and bottom) are bolted to the motor casing. On the right hand side, there's a black wire which goes from a spade connection on the rear of the unit to what looks like a grounding stud on the motor casing. At the front of the unit, one black wire connects top to bottom, and a black wire from top and bottom return down the boat via the choc box.

The bow thruster is a 24 volt one, although the boat is mainly 12 volt, so this adds an additional bit of complexity. The 24v is created by a widget which temporarily puts the dedicated bow thruster battery in series with the domestic bank. I'm assuming this is working as expected because, on the contactor, when I put a voltmeter across from the input stud to one of the spade connectors I'm getting 12v constantly, but 24v when the bow thruster control is operated. However, no response from the contactor. What tests could I do to confirm that the contactor has failed? Also, is it possible that in fact the error lies elsewhere (I'm assuming not because I'm getting 24v, but it's probably a lot more complicated than that!)

Anyway, if it helps anyone help me, below is the picture of the wiring diagram left to me by the previous owner of the boat which explains the elaborate relay system. Is there anything there that looks like a likely failure point?

If anyone has read this far, thank you so much for your patience! If anyone can additionally point me in the direction of some tests I could do, I would be most grateful.

 

[superheat6k]

Are there three heavy connections onto the thruster motor, or just two ?

i.e. is there a left coil and right coil with common negative, or just one motor coil that is polarity reversed.

Did it work OK or has it always been not working ?

I am wondering why the red is vacant from the choc block.

I would disconnected the heavy feed then check each relay is working by applying 12 volts. If the changeover relay bottom left doesn't move to one position or the other the 24v circuit may not be created.

Do you hear any of the relays clicking.

Is there a 12v feed from the Ign live relay shown on the right. If there is no power here then the switch has nothing to control.

Is the heavy solenoid armature where the heavy relay contacts are free to move ?

 

[Ian_Edwards]

This looks very similar to the contactor which failed on the Lewmar bow thruster on my boat.

Lewmar have a method of testing the contactor and they emailed me a copy of it. If you PM with our email address, I'll forward it to you.

In my case the thruster, a 12 volt 5kW 185TT, would only run in one direction. I finished up buying a new motor and contactor, which was very expensive, but I had a deadline to meet, so had no option.

I also have the maintenance manual for the 185TT, I know it's a different make and model, but it may have some useful info', all the bow thrusters seem to use very similar components, no doubt sourced from the same suppliers. So if you'd like a copy let me know.

On the Lewmar, as far as I can tell all the switching is done on the negative side, so take care when testing, although it's low voltage, there can be 100's of amps available to generate big sparks!

I've sent my motor and contact or to a rewinding company in Aberdeen, but have yet to find out if they can repair it.

 

[rogerthebodger]

It looks like the same type of contactor on my Vetus bow thruster.

The motor is a series wound motor ie separate rotor and field windings. To reverse the direction of the motor you reverse the current in either one but the other stays the same direction

Have a look here

http://www.ybw.com/forums/showthread.php?446694-Bow-thruster-wiring-and-solenoid

http://www.ybw.com/forums/archive/index.php/t-322513.html

 

[bozlite]

Are there three heavy connections onto the thruster motor, or just two ?

i.e. is there a left coil and right coil with common negative, or just one motor coil that is polarity reversed.

The set up is like this, I think:

In my first picture, the big copper strip disappearing to the left goes to the field, and there are two connections to the armature (the top one of these is visible in the picture). So current flows one way or another through the armature depending on switch position.

Did it work OK or has it always been not working ?

It used to be fine.

I am wondering why the red is vacant from the choc block.

Yup - me too! There's definitely no spare wire floating about anywhere, though.

I would disconnected the heavy feed then check each relay is working by applying 12 volts. If the changeover relay bottom left doesn't move to one position or the other the 24v circuit may not be created.

Do you hear any of the relays clicking.

Is there a 12v feed from the Ign live relay shown on the right. If there is no power here then the switch has nothing to control.

Thanks, yes. I'm thinking it might be more to do with the relays. I'm getting 24v on the big red, but I haven't checked that I'm getting it on two cables in the choc-block going to the contactor coils (top right relay, I think).There's been a fair bit of electrical work done on the boat recently, so it's possible something has been disturbed. I think that's more likely than the contactor failing?

Is the heavy solenoid armature where the heavy relay contacts are free to move ?

Yes. And thanks for taking the time to respond.

 

[bozlite]

This looks very similar to the contactor which failed on the Lewmar bow thruster on my boat.

Lewmar have a method of testing the contactor and they emailed me a copy of it. If you PM with our email address, I'll forward it to you.

In my case the thruster, a 12 volt 5kW 185TT, would only run in one direction. I finished up buying a new motor and contactor, which was very expensive, but I had a deadline to meet, so had no option.

I also have the maintenance manual for the 185TT, I know it's a different make and model, but it may have some useful info', all the bow thrusters seem to use very similar components, no doubt sourced from the same suppliers. So if you'd like a copy let me know.

On the Lewmar, as far as I can tell all the switching is done on the negative side, so take care when testing, although it's low voltage, there can be 100's of amps available to generate big sparks!

I've sent my motor and contact or to a rewinding company in Aberdeen, but have yet to find out if they can repair it.

Great, thanks - I'd like the contactor test instructions. I've sent you a pm.

 

[bozlite]

It looks like the same type of contactor on my Vetus bow thruster.

The motor is a series wound motor ie separate rotor and field windings. To reverse the direction of the motor you reverse the current in either one but the other stays the same direction

Have a look here

http://www.ybw.com/forums/showthread.php?446694-Bow-thruster-wiring-and-solenoid

http://www.ybw.com/forums/archive/index.php/t-322513.html

Thanks for that - yes, similar to the diagram I just posted in rely to superheat6k.

And thanks for the links - they'll make for interesting reading.

 

[superheat6k]

You mention some other electrical work - this is where I would start.

I don't believe in coincidental faults like this, too often work nearby can inadvertently knock or disturb something else.

I would start by applying a jump feed to each relay with the heavy power turned off to see what relays are or are not working, then work back to see what signals are and are not being received if any do not work.

Unfortunately it is not viable to provide a detailed list of electrical diagnosis procedures for every situation. If you do get stuck find a decent auto or marine electrician to assist.

If your near Hamble I would be pleased to have a look with you. Most electrical issues like this turn out to be something daft.

I found a new looking Par Mate 2.5 GPM water pump in the boatyard bin last week. Ten minutes with a philips screwdriver, reset the rubber discharge valve back into its seat and I now have an as new spare pump.

 

[bozlite]

You mention some other electrical work - this is where I would start.

I don't believe in coincidental faults like this, too often work nearby can inadvertently knock or disturb something else.

I would start by applying a jump feed to each relay with the heavy power turned off to see what relays are or are not working, then work back to see what signals are and are not being received if any do not work.

Unfortunately it is not viable to provide a detailed list of electrical diagnosis procedures for every situation. If you do get stuck find a decent auto or marine electrician to assist.

If your near Hamble I would be pleased to have a look with you. Most electrical issues like this turn out to be something daft.

I found a new looking Par Mate 2.5 GPM water pump in the boatyard bin last week. Ten minutes with a philips screwdriver, reset the rubber discharge valve back into its seat and I now have an as new spare pump.

Thanks, that's all good advice. I'll see what I can find this weekend. And thanks for the offer of help - unfortunately, I'm up in Nottingham!