Hardinge HLV-H Uncontrollable Speed Changes

Hey guys,

We have a Hardinge HLV-H here at work, and when you trigger the Faster/Slower switch, the lathe just takes off in either direction. I noticed that the contactors (Essex 101140) are sticking to the point where we have to turn the machine main power off and let them de-energize. Is it actually the contactors sticking, or is it in relation to the speed cam assembly? Before I start taking stuff a part, I'd thought I'd ask. Thanks!

Before you do anything else, does the spindle turn the correct direction when the forward/reverse switch is turned forward? If not reverse the input wires going to L1 and L3 in the cabinet.
If the spindle is turning the right direction and no one has changed any of the original lathe wiring then you have another fault that I have no experience with.
The vari-drive motor is 3 phase also and when a machine is moved and the spindle phasing is reversed the vari-drive will run the wrong way with out the proper limit switch being contacted. This will cause a lock up and the screw will need to be turned by hand to get it off the switch. They usually run correctly after the phasing is corrected.

FredC said:

Before you do anything else, does the spindle turn the correct direction when the forward/reverse switch is turned forward? If not reverse the input wires going to L1 and L3 in the cabinet.
If the spindle is turning the right direction and no one has changed any of the original lathe wiring then you have another fault that I have no experience with.
The vari-drive motor is 3 phase also and when a machine is moved and the spindle phasing is reversed the vari-drive will run the wrong way with out the proper limit switch being contacted. This will cause a lock up and the screw will need to be turned by hand to get it off the switch. They usually run correctly after the phasing is corrected.

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I can verify the phases again, but this machine has been running for 20+ years here fine (wouldn't shock me if it has been wired wrong the whole time though). If you lightly trigger the toggle switch (it's a newer style without the buttons), it will pulse, but if you hold it too long, something gets stuck and the lathe speed takes off. We have to kill the power and wait until the contactors/relays pop out before we can run it.

Apparently the machinist has been running at two speeds for quite some time because of this issue. He said it has gotten worse.

I'm not sure what the 'speed cam assembly' is. The speed change is performed by a small motor driving a screw, so I think you're on the right track on the contactors sticking.

When that kind of thing happens on my machine it is always the vertical cam assembly switches. The cam is the main point of control to you speed contactors. The cam lobes rotate and press down on switches that control the power to the contactor coils. There is a piece of phenolic that extends out of the switches that holds a set of points. I have had to repair the switches and make new phenolic pieces.

The original phenolic pieces are on the right. The right side is rounded over and makes contact with the cam lobe. The right side has a hole that holds the set of points. The open/close operations eventually burn up the phenolic piece and they erode away causing faulty switch closing and opening. The pieces on the left are new spares I made for future repairs. It is good that those switches can be disassembled, at least in my model year.

You might get lucky and find that a simple disassembly and clean of those cam switches are all that is needed.

The speed jack contactors are a linked pair. I suspect the mechanical linkage is sticky or damaged , causing the contact to jam. OR. the contacts are so badly worn , that they are welding on contact .

Either way, I'd look at repacing the pair. . You'll probably have to find a proper industrial supplier to get the interlinked version. (the interlinking prevents a direct short circuit in the event that one contactor is jammed)

Bill

Just to be clear "speed cam assembly" what is that?
I think older lathes may have had a speed change cam assembly like my Tsugami chucker (Japanese copy of an HC). My HLV-H does not have that. Cams do actuate the switches though, I guess a cam or switch could stick. Old dry lube or a stuck contact have already been mentioned could be the cause.

If the machine has not been moved and no one has messed with the 3 phase leading into the building my original suggestion is unlikely.

FredC said:

Just to be clear "speed cam assembly" what is that?
I think older lathes may have had a speed change cam assembly like my Tsugami chucker (Japanese copy of an HC). My HLV-H does not have that. Cams do actuate the switches though, I guess a cam or switch could stick. Old dry lube or a stuck contact have already been mentioned could be the cause.

If the machine has not been moved and no one has messed with the 3 phase leading into the building my original suggestion is unlikely.

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The speed cam assembly literally looks like a car engine cam, but plastic, with lobes and all. The lathe has a lever that has two speeds on it based on the direction you pull it.



You can see the cam to the right of the main fuses. The picture shown is of the same model as ours at work. When the speed is changed via the toggle switch, I see the contactor, first two under the fuses depending on faster or slower selection, click on put stay in that position and the lathe ramps up or down. Now, those contactors have little adjustable setscrews in the center, can those be adjusted at all?

But my main question was on the function of the little switches on the cam. Also, is the cam supposed to rotate/spin, or does it just pivot? I don't think ours spins if that's the case.

the cam switch enables power to the jack direction contactors .The worst it could do is lose a phase , it cannot jam the direction contactors.

There's no adjustments on a contactor. if it is jamming mechanically (or welding) it wil stay closed with the power off (at least until cooler ) .


There could also be a problem with the up/down switch (normal failure mode is to just stop working). The later twist operation switches generally seem crappier than the older style push buttons (the pull-on estop is pure crap).

if it's jamming up and down, replace the contactor pair .

Billtodd said:

the cam switch enables power to the jack direction contactors .The worst it could do is lose a phase , it cannot jam the direction contactors.

There's no adjustments on a contactor. if it is jamming mechanically (or welding) it wil stay closed with the power off (at least until cooler ) .


There could also be a problem with the up/down switch (normal failure mode is to just stop working). The later twist operation switches generally seem crappier than the older style push buttons (the pull-on estop is pure crap).

if it's jamming up and down, replace the contactor pair .

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They are jamming and last well past cutting the main breaker power to the machine.

Any clue on where to find these contactors, or off the shelf modern replacements?

Rob,

It might just be a mechanical problem, if they are sticky for a few minutes perhaps it's fixable (looking at these prices you have a few hours to spend before hitting replacement cost)

Contactors | AC Mechanically Interlocked IEC Contactors | Product Catalog Search Results | Galco Industrial Electronics

Omron ones (RS list a J7KNA-12-10 24D but this is 24vdc and there's no picture) appear cheaper. You'll need to know the coil voltage, usually 110vac, and contact rating (fractional horsepower) they often have a normally closed electrical interlock contact in addition to the 3ph contacts

Bill