Hardinge HLV-H electrical problem

Hi All,
I had a problem with my HLV-H (UK made) where it was sitting powered up but not actually running when the mains trip popped. Fault finding led to the main fuse in the lathe's L1 input blown. Replacement blew too. This turned out to be an earth fault on the transformer. New transformer wound (three months!)and fitted last week. N.B. Whoever decided to locate the mounting screws behind the windings in the darkest corner of the cabinet deserves Karma in spades.

Now I find everything powers up OK and the motor runs fine in low range but as soon as I engage high the L1 fuse blows again.

Before I head off on a wild goose chase, I'm looking for some advice.

Could this be the result of a cock-up on my part (entirely likely) in wiring up the transformer? I don't see how it could affect the motor, but wise heads might know better.

Can a second insulation breakdown have occurred at the same time in the motor circuit? Seems a bit of a coincidence, but who knows?

How best to troubleshoot this?
Advice is sought!


REgards, Jim

You should have asked on here for a transformer ! (I've one sitting in the garage )

The motor windings are separate for the hi and low speeds , so it is possible to have a shorted winding on one winding with out effecting the other (I sincerely hope not) .

You'll need to test the insulation of the HS windings and wiring to them (there's always a chance the insulation has been damaged where the wires exit the electrical cabinet. A simple ohms meter will do a quick test , but if you can find a high voltage tester it'll give you a better check.

Can a second insulation breakdown have occurred at the same time in the motor circuit? Seems a bit of a coincidence, but who knows?

Click to expand...

Had any electrical storms lately? (I find it odd that the original transformer has failed - they are good quality units)

Bill

Billtodd said:

You should have asked on here for a transformer ! (I've one sitting in the garage )

Click to expand...

I should, shouldn't I? Thanks, Bill, but too late now.

Electrical storms are common enough here; there wasn't on over us at the time but might have been one elsewhere on the island. Voltage surges aren't unusual either ( but less common after the interconnector to the UK)

I'll see what I can find tonight with the ohm meter.

The transformer was definitely blown. Found that with a megger and had it thoroughly tested by someone with more idea than me.

At the time of original failure none of the breakers on the machine popped - or have during subsequent buggering about.

I must admit, the electrical load when the spindle motor kicks in on HS is considerable; as the last building on the mains supply we only get 20A/phase and the lights used to go dim when the motor kicked in!

I find it odd that its always L1 that blows, which suggests car2's ideas on the low voltage side need checking too.
I'll get on to it this evening.

Thanks guys

regards, Jim

I used to see the voltage drop when I was running on a phase converter and it was this that made me install a 3 phase supply since when it hasn't been noticeable.

The fuses are 20A, and look powder filled so presumably slow blow type. I have some 32A on the way and will try one of those in the offending phase. I'm hoping that its just transients on start-up that are causing the problem, especially if the new transformer which is on the offending phase is taking more draw. We'll see.

OTOH, the Isle of Man is reckoned to have the potential to put a man in orbit: who knows,it could be me.


Jim

car2 said:

There is something that is drawing abnormally high current (maybe a shorted winding on the brake solenoid, etc?). Good Luck, Cheers Charles

Click to expand...

Yeah. This machine is 415V; that's on reason I'm a little bit circumspect when working on it. Those who have survived such things tell me that a belt across phases really hurts. Others don't get to tell me anything.

However, as 415V, I'd expect the current for a 1.5HP motor to be no more than 2 - 3 A when running.

There seems to be a lot of suspicion about the brake solenoid. As I've never actually used the brake, I wonder if it might be better simply to disconnect it. What baffles me is why the low speed works but not high.

What I really need is a UK schematic for the electrics, but I don't have one and can't find much online

Jim

So the 32A fuses finally arrived and replacing just the L1 fuse seems to have solved the problem in as much as the machine actually run now.

I do have concerns regarding what must be increased current draw but I'm inclined to take a wait and see approach there.

Re the brake solenoid, it does seem noisy when the brake is "off". Car2; I have taken on board your suspicions and I'm inclined to disable it on general principles. I have, however, just taken a hit on my left knee so I don't feel like grubbing about behind the motor just now because it hurts enough to be a distraction.

I did manage to obtain the electrical diagram for a UL built HLV-H for Dubai - 380V - but it's Hellish faint. Once I decipher it I'll probably disable the brake at the board.

OTOH, maybe I'll just quit while I'm ahead.


My thanks to Bill and Car2 who responded; it helped.

Regards. Jim

Is this a KL1 or a HLV-H
There is some difference in the electrical diagram I thought

Peter

re noisy brake soloniod

check the copper links on the armature (moving part) they maintain the magnetic field as the current alternates ,if they are opencircuit (cracked) they won't work)

bill

Billtodd said:

re noisy brake soloniod

check the copper links on the armature (moving part) they maintain the magnetic field as the current alternates ,if they are opencircuit (cracked) they won't work)

bill

Click to expand...

I seem to have no armature movement at all, so I suspect that you're right.

I have disconnected the brake solenoid and that quietened things down no end! With the cork backed off the machine is usable again and that's good enough for me.

To be honest, I found the brake a damn nuisance, with oiling the drum and all that, combined with the ramshackle arrangements for removing / replacing the panel so now I'm happy again.

The one thing I've not actually tried is replacing the uprated fuse with the specified 20A, maybe when I'm in an experimental mood I'll do that. Trouble is, if the 20A blows, I'll go back to fretting about it so I'm probably best to keep my head in the sand. Sounds like a plan!

Thanks once more for the advice; much appreciated.

Jim

car2 said:

If the brake was dragging all the time when the spindle is running , that might've been loading the motor considerably. (I kinda like the cork brake, since I'm a keepit-simple-stupid sort of person (and it's reliable and the cork can be gotten from the hardware store))... Glad you're up and running, Cheers, Charles

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Hi Charles,

The brake never worked, cork worn out and backed off, so no drag there.

Have to say, if the factory saw fit to put it on, I'd like the brake to function, but I'll settle for life without it.

Up and running will do.

Thanks again man,

Appreciated.

Jim