Electrical Puzzlement

[Dan]

Hi all.

My major winter project this year is to get my VERY sluggish/unusable windlass (Simpson Lawrence Anchorman, '99 vintage) running well again. I soaked the corroded parts in vinegar (works well, btw). I disassembled all the moving parts and lubricated them. I removed the motor and cleaned the contacts. The brushes are good. The relay works well.

I checked voltage. Under no load, there's 12+ volts at the motor terminals. Under load, that drops to 1.8. I couldn't believe it was that much of a drop, but I couldn't get it to read anything but that.

The schematic says the circuit is as follows:
starter battery -> starter battery switch-> dedicated circuit breaker -> relay -> motor terminal (+) -> motor -> motor terminal(-) -> ground

Under load, the house lights dimmed, which surprised me because, as you can see, it's supposed to be connected ONLY to the starter circuit, isolated from the house. I found continuity from the starter (+) to the house (+).

Also, the (+) lead to the relay was hot even when the starter battery switch was off (likely the house current).

Could it be something to do with the galvanic isolator? Where do I even begin to troubleshoot this one? And why would voltage drop so dramatically -- the corrosion can't be THAT bad, can it?

 

[Don S/V ILLusion]

Not sure I fully understand your circuit description but based solely on the 1.8 V reading, it sounds like the motor winding is shot and shorted which would explain the problem you described when trying to use it.

A galvanic isolator is on the AC side of your power, not DC.

To troubleshoot the motor winding, test for continuity and any obvious physical problems like binding when trying to turn the motor

 

[Ed Schenck]

You must mean a "battery isolator". Sounds like it has failed allowing current draw from the house batteries. Or can the draw be higher than the isolator can handle? Not sure of the innards(big diode?) on those. But I agree with Don, seems like the motor is shot.

 

[Don12364]

Dan,
You need an ammeter in circuit (series) with the windlass motor - just temporarily whilst you diagnose the problem. It'll need to read to over 50 amps to test on load but 25 amps for off load testing is okay. A crude ammeter from a car dashboard or one of those dreadful cheap clip on ones seen in auto shops would suffice. When I serviced my windlass I put it onto a car battery in my garage just to make sure all was well. From memory the no load current is about 10 - 15 amps and this rises to over 70 amps at stall. I tested a range windlasses for a UK sailing mag and they were all about the same. If the no load current is high and the mechanism is not binding then suspect the motor as Don 'van' Illusion advises. New motors can be procured by finding the maker and going direct. None of the windlass manufacturers make their own motor.
If the terminal voltage dies before the current reaches a sensible figure then there is high resistance in the wiring. You didn't say whether it was ever okay in the past.

For info my system came wired with the control side of the circuit (up/down switches and circuit breaker coils) connected to the house bank but the main windlass motor was on the starter battery via the breaker contacts. This sounded odd because it meant both batteries need to be good to use the windlass. However it does mean that the volt drop caused by the windlass on load cannot cause the CB to chatter in and out.
Your system may be wired as mine. Try following the wiring and persist until you find the cause.

 

[RanAweigh]

That scale of "voltage drop" is indicative of pretty much a dead sort.

 

[tommays]

Well

One way to test is to measure the voltage at the battery and see how much it drops compared to the voltage as close to the windlass as you can.

If you work your way back through the different conections you will find were it is losing power and remenber the NEG wire is just as inportant

If your good at the battery BUT low at the windlass then your droping voltage becasue of bad wires or connections


Yor dimming the cabin lights which sounds like a large draw from the windlass

 

[Benny]

Check that the wiring gauge is appropiate for the round trip distance to the battery. Check all connections.

 

[Dan]

Thanks everyone. I'm still confused, but you've given me some things to look at.

Don: I don't think it's the motor - I hooked up one of those emergency starter batteries directly to the terminals and she ran like a charm.

Donalex: I don't know if she ever ran well; it never ran well for me. I bought it 2 yrs ago. Like your windlass, my control box (solenoid) is wired to a separate circuit breaker in the panel and run by the house batteries. My multimeter doesn't read amperage that high, so I'll look for a dedicated ammeter that does.

Tommays: if I understand correctly, you're saying that if the problem is corrosion in the wiring, the battery whould be pumping out ~12v, and would show up at the motor as ~1.7v. I'll test that.

I still don't know why the house batteries would be involved at all when the circuit is supposed to be connected to the starter battery only. I think this is a clue that wires are crossed -- as RanAweigh suggests.

 

[tommays]

If it does run correctly on the test battery then you will have to look at wire size and the condition of wires and connections

On common problem is called BLACK WIRE and if you were to remove the jacket the copper will be BLACK which means it is dead

 

[RanAweigh]

Dan - It sounds to me as if you are well on the way to troubleshooting the problem.
If the windlass motor runs "fine" when powered by your jump start pack then the motor is most likely good. Once you know what components of the "system under test" are good you are on your way to success.

Next. Test the overall resistance of the wiring from the windlass back to the switch. With the meter set to resistance or continuity and one wire at a time, put one lead of your multimeter at the switch and the other at the terminal on the windlass. Resistance should be pretty close to zero. If it is go back one level. Check from panel to switch. If the resistance is high the wire (size or condition) may be your gremlin.

Troubleshooting is a lot like making a sculpture of an elephant. Begin with a big block of stone then remove the parts that do not look like an elephant.

 

[Stu Jackson]

While you're at it

draw yourself a wiring diagram. That's the ONLY way to find out how it's wired, because without that, we're ALL only guessing. As Donalex said, the control side could be wired to the hosue bank and the power to the motor to the reserve bank. Were you running your enigne when you took the measurements?

With electrical stuff, it's almost ALWAYS the connections, then the wiring.

When you say "I don't know," then it's time to FIND OUT.

 

[Bill Roosa]

Connections

Since the house lights did not go out I suspect that the batteries are trying to supply the voltage but it can't get to the motor. If it was a dead short then the house lights would go out and the batteries would make "funny" sounds from being shorted.
You know about voltage drop across a connection just trace from battery + to motor to battery -, one or more of the connections will be the culprit.

Good luck

 

[Pat T]

Twice, corrosion got me

Water got where it shouldn't have been and caused me many hours to trouble-shoot. One time I had a leak in a bilge hose and water spilled into the corrugated casing holding the wire. The problem was at a crimped connector. Where I expected to find a continuous wire I found a joined (by crimping) wire. That's were the wire actually disconnected and I lost lighting in half the boat. Similar situation in the bilge with the pump. Again, it was at the crimped connection. You will find it eventually.