Drying out a large electric motor

Gentle warmth like this should do the trick. You should be able to join all three ends of the star and feed your battery charger between this junction and the star point to increase the dissipation to 13 watts per phase assuming your battery charger can supply this OK. Are you sure the leakage is in the motor itself? It could be due to the starter housing a few dead spiders etc.

Good Luck

Bob

I got one going years ago, that had been flooded with vanilla syrup. It was in a milkshake machine at a fast food place. I offered them 50% off on the labour for the motor when I replaced it with a new one. I took the motor apart, and boiled it in fresh water for several hours. after that it was place in the domestic oven for 2 hours 65 C. After that treatment, the motor ran well, and was put to work in my metal cutting band saw. when it gets hot, it still smells of vanilla! In you're case, it may have salt in it from the rain.

Steve R.

An Alba 3S 18" shaper followed me home last week. In suprisingly good order considering it's been under a tarpulin in someones garden for something like five years. Motor windings are leaky to the case as you would expect - about 300K to 1/2M ohm.

It's about 5 HP open frame and driven through a Memota star delta starter. I've rigged it up to a battery charger across one winding disipating 13 watts to warm it up a bit, and it's in a dry and temperature controlled area. I'll cycle round the other two windings as time passes.

Any other suggestions to dry it out before I take the plunge and wire it up? I may end up replacing the motor, but don't really want to as it won't 'look right' !

AWEM

windings

Good idea - I've paralleled the windings, and am running them off a

24v bigger charger as the 12v one wasn't up to the job. Now dissipating about 78 watts which I reckon shouldn't fry anything spread across the 3 windings. Leakage was down this morning to over 1M ohm just having warmed the one winding off 12v. Good progress I reckon.

AWEM

The standard treatment for wet motors in the military was to drench them in Hellerman Fospro. I've seen it used on a number of large motors which had been immersed in dirty water for a week. They were hosed down to clean them, liberally anointed with Fospro, left a day to dry and worked perfectly.

(Page 184 as pages numbered).

Very nice smell as well.

Aaah Fospro...

a.k.a. NATO WD40

>

And B.T. Spray Dewatering 1A - just used my last can, not bad considering I took the Release '93 redundancy package!

Dave H.

windings

OK a day with 78 watts warmed the motor 11 degrees above ambient and increased the resistance to frame to something over 4 Meg Ohm - so motor connected and running amazingly sweetly considering what it's been through.

AWEM

Local quarry near me floods every year, they shut the power off to the machines in the quarry and leave them, When the water level has dropped they hose the motors off and stick a cut down 45 gallon drum with a load of waste wood and a drop of diesel right next to the motor, light it, let it burn down then start up.

Every 3 years or so they take them off and the local rewinders dry them out in the oven and fit new bearings.

Large three phase motors are very resiliant.

John S.