Did my electric winch damage my alternator?

[chrisedwards]

Just wondering why my alternator on my Beta BD722 suddenly decided to put out 18 volts (according to mechanic) and overheat - make nasty burning smells. I had to change it at a horrendous cost. Co-incidently I had, in the previous week, used my electric winch to heave up my 700pound centreboard - for the first time - about one min and very heavy - 30 showing on ampmeter and engine on. (I always use an adjacent manual winch). The engine/alternator is ten years old and run for only 400 hours.

Please could someone reassure or warn me.

Many thanks

 

[wotayottie]

Sounds like the voltage control regulation has broken and in this situation a really heavy load from the winch would cause an excess current flow.

was the battery flat? Is there a problem with the battery feed to the windlass?

But no way should using a windlass knacker an alternator that has no other fault.

 

[Monique]

Electric winches are normally hooked directly to the house batteries and if yours are in good condition, you should not have had this problem as the alternator only recharges the batteries.

The work you assigned on your poor winch was high. If it stalls or slows dramatically, you are creating a severe overheat within the motor.

Hopefully, it was an unrelated issue which caused your gene to fail.

GL

 

[charles_reed]

Just wondering why my alternator on my Beta BD722 suddenly decided to put out 18 volts (according to mechanic) and overheat - make nasty burning smells. I had to change it at a horrendous cost. Co-incidently I had, in the previous week, used my electric winch to heave up my 700pound centreboard - for the first time - about one min and very heavy - 30 showing on ampmeter and engine on. (I always use an adjacent manual winch). The engine/alternator is ten years old and run for only 400 hours.

Please could someone reassure or warn me.

Many thanks

Unlikely to be the winch - recon alternator from a reasonable auto-electrician about £50, replacement from same source about £110.
Usually bridge diode burnt - for this reason I always carry a replacement alternator - with a smart controller it happens, though the 110 amp Magnetti Marelli seems to have cured the problem for the last 3 years.

 

[lw395]

It is possible that a voltage spike from the winch motor has taken out the regulator.

The motor is an inductive load, when you switch it off, a voltage spike may occur. This can be seen as arcing across relay contacts etc.

Most automotive stuff is fairly well protected, as it's not ever so different from a starter motor for instance, but it is possible to add more protection in the form of avalanche diodes, RC snubbers, suppressors etc.

Alternatively, one of the secondary diodes feeding the regulator has gone. This could be caused by alternator overheating, if the airflow around it was very poor and the engine compartment already hot. Boat alternators are more prone to filling with fan belt dust etc which stuffs the cooling.
The heavy load of the winch would cause the alternator to be running at max output.

Looking at the old alternator might give some clues.

I am assuming you don't have an external regulator such as stirling or TWC?

Hope that helps?

 

[VicS]

The motor is an inductive load, when you switch it off, a voltage spike may occur.

But with a battery connected you expect that to absorb any spikes that might otherwise kill an alternator connected directly. No??

 

[lw395]

But with a battery connected you expect that to absorb any spikes that might otherwise kill an alternator connected directly. No??

You might hope so, you might be disappointed!

The high frequency impedance of batteries is a complex (pun intended) subject. I played around with one of those 'desulphator' circuits, which could put 50V spikes at the battery terminals without using very much power. I concluded that batteries are not that good as spike suppressors.

YMMV

Cheers,

 

[grumpygit]

You might hope so, you might be disappointed!

The high frequency impedance of batteries is a complex (pun intended) subject. I played around with one of those 'desulphator' circuits, which could put 50V spikes at the battery terminals without using very much power. I concluded that batteries are not that good as spike suppressors.

YMMV

Cheers,

I would not really envisage the possibility of a permanent magnet motor creating a spike by capacitance to damage a regulator. But you are correct, a battery is a very lazy spike suppressor.

_____________________________________________________________________

 

[lw395]

I would not really envisage the possibility of a permanent magnet motor creating a spike by capacitance to damage a regulator. But you are correct, a battery is a very lazy spike suppressor.

_____________________________________________________________________

It's a big old motor, high current. It will be inductive, so the spike on switch off will not be small.
Maybe an unfortunate loading of wiring and other inductive loads has created a resonance?
All these things are possible, but auto stuff is usually fairly tough.
But alternators rarely die before 100,000 miles in cars, but they do now and then.
Could be coincidence, or we could look for possible causes.
We are only making educated guesses based on previous broken stuff we've seen.
It would be interesting to get in there with a scope and try to blow it up again, but I don't think I'm going to do that right now!
The question is does the OP want to chance it happening again I suppose.

A surge suppressor diode close to the motor might help, if the motor is the cause.
Some chunky suppressor caps, possibly with 10ohm 1w resistors in series won't hurt either.

Equally I would not rule out the thermal overload theory, or the possibility that something was weakened by aging in a salt atmosphere and a moderate load finished it off. In which case it's probably OK for another 10 years or whatever.

It's a grey area of electronics. (except when it's the black scorched area of electronics.)

 

[chrisedwards]

It is possible that a voltage spike from the winch motor has taken out the regulator.

The motor is an inductive load, when you switch it off, a voltage spike may occur. This can be seen as arcing across relay contacts etc.

Most automotive stuff is fairly well protected, as it's not ever so different from a starter motor for instance, but it is possible to add more protection in the form of avalanche diodes, RC snubbers, suppressors etc.

Alternatively, one of the secondary diodes feeding the regulator has gone. This could be caused by alternator overheating, if the airflow around it was very poor and the engine compartment already hot. Boat alternators are more prone to filling with fan belt dust etc which stuffs the cooling.
The heavy load of the winch would cause the alternator to be running at max output.

Looking at the old alternator might give some clues.

I am assuming you don't have an external regulator such as stirling or TWC?

Hope that helps?

Many thanks for such useful replies. I am in the process of allowing more ventilation into the engine compartment and yes the alternator was absolutely smothered in fan belt dust - I used to cover the alternator when cleaning engine.

Is a better safe than sorry policy of using the electric winch, with the engine off, worth adopting please?

 

[Dockhead]

Many thanks for such useful replies. I am in the process of allowing more ventilation into the engine compartment and yes the alternator was absolutely smothered in fan belt dust - I used to cover the alternator when cleaning engine.

Is a better safe than sorry policy of using the electric winch, with the engine off, worth adopting please?

30 amps is not a huge load. I cannot imagine that you need to worry about the alternator. Our bow thruster can draw more than 600 (!) amps at 24 volts, about six times the alternator's peak output, and we certainly don't worry about it harming the alternator. You will have a momentary big starting rush which will, on the contrary, pull down your voltage. Did you have electronics switching off when this happened? If you didn't even have electronics switching off, then it's hard for me to imagine that your electric winch has done anything so drastic that it's killing alternators. Maybe it was bad already and the load pushed it over the edge.

I would just use it, if I were you. I wouldn't really want to use the winch without the engine switched on because then you'll reall pull the voltage down. It's generally recommended to have engine running when using high current devices. On my boat there's even an interlock to prevent windlass and bowthruster from being operated without the engine running.

 

[Appletree]

You'll never know

Truth is you'll never know whether the winch caused problem or was just a coincidence.

However I'll guarantee that LSUK could repair your old alternator or supply new on at a fraction of the cost of marine version. Also meta engines are based on kubota blocks so also try kubota gents for generic spares.

 

[chrisedwards]

30 amps is not a huge load. I cannot imagine that you need to worry about the alternator. Our bow thruster can draw more than 600 (!) amps at 24 volts, about six times the alternator's peak output, and we certainly don't worry about it harming the alternator. You will have a momentary big starting rush which will, on the contrary, pull down your voltage. Did you have electronics switching off when this happened? If you didn't even have electronics switching off, then it's hard for me to imagine that your electric winch has done anything so drastic that it's killing alternators. Maybe it was bad already and the load pushed it over the edge.

I would just use it, if I were you. I wouldn't really want to use the winch without the engine switched on because then you'll reall pull the voltage down. It's generally recommended to have engine running when using high current devices. On my boat there's even an interlock to prevent windlass and bowthruster from being operated without the engine running.

sounds good - many thanks

 

[lw395]

Dockhead is right, it's better to have the engine running.
The alternator is connected anyway.
Possibly worth keeping an eye on the dust situation, give the alt a clean (compressed air?) now and then?

 

[eagleswing]

fan belt dust? yikes ....

if your alternator was' covered in fan belt dust ' i hope you replaced the alternator belt and any other v belts of similar age, e.g. the water pump drive belt, etc. black dust from a belt is a sign of impending belt failure which could happen at of course the least convenient time.. such as when you need your water pump to cool your engine which is operating at max rpm to get you past the alderney race...

 

[chrisedwards]

Many thanks for reassuring replies. Yes I will use air blast cleaning. Dust and belt problems seem endemic with Betas but I have changed the belt and checked alignments etc. I wish I had asked for the old alternator form the mechanic.