Hardinge HC spindle variable speed won't change speed troubleshooting info

hitandmiss · Feb 27, 2018

Hardinge HC troubleshooting info for variable speed change problems

Over the years several people have had problems with the HC variable speed unit that will not change speed properly.
The main problem starts with the electrical drawings are never with the machines and appear to be hard to find.
Coupled with a couple of not so obvious flaws that lead to very unexpected results see ****CAUTION**** below when trying to work on one of these with no prints.

The schematic shown here is from CHB-8220. It is an early print from 1980.
The info shown should be close enough to trouble shoot speed control problems.

Component identification:

1DS Closed when spindle is running.
SS3 Selector switch to turn variable speed on or off.
2LS Limit switch to stop speed change motor when at end of travel.
2MR Contactor to run speed change motor to raise speed.
2ML Contactor to run speed change motor to lower speed.
2CR Plug in relay to control 2MR.
3CR Plug in relay to control 2ML.

Spindle must be running and SS3 turned on to change speed.
If speed is at maximum or minimum either 2 CR or 3CR will be pulled in, these relays are plug in and can be switched.
If the same problem persists, the next thing to check is the transistors located in the speed control station.
They are in sockets and can be switched. The top one operates 2CR for increasing speed. The lower one operates 3CR for lowering speed. If the attached relay is always on, the transistor is probably shorted E to C.

*** CAUTION**** Be advised, before manually operating either 2MR or 2ML, remove 2CR and 3CR. There is no manual or electrical interlocks for 2MR or 2ML and they can both be closed at the same time and cause real problems. If the speed is stuck at either limit, the appropriate contactor will have power as soon as you jog off the limit, and if you are holding the other one in, it gets ugly fast!

If the speed is midway and not able to be changed, see below picture:

The small transformer at the lower left should have 115-120 Volts between wires 8 and 20 (the lower terminals).

The complete print is here:

Bill

Wow, under "go advanced" when editing, you can edit the thread title, but it doesn't seem to update on the forum every time.

rdn2blazer · Mar 18, 2018

Very happy I found this thread. My Hardinge is stuck at the low rpm range. And I know nothing about electrical. I have a guy but he has never worked on this stuff I know. Are their machinery repair shops for this stuff? Looks like I will be google searching.

readymix · Mar 18, 2018

Rob,

Brian from CK5 here! Ben a long time, how's things going at your shop?

I'll look at your machine next time I'm in your area. Not sure when that will be though.
Still have your HAAS mill?

Was in LA last week repairing a press brake, and I know we are going back.

rdn2blazer · Mar 19, 2018

Hay man how’s it going? Yes still have the Haas. Have a few things powered so far, Haas included. You have my number? Let me know

hitandmiss · Nov 26, 2018

Today I was a customer where I had repaired their HC over a decade ago.
When I did the repair the Hardinge contactors 2MR and 2ML were damaged beyond repair.
So I replaced them with suitable contactors and circuitry so the damage could never happen again.

Newer Hardinge systems use the NC Aux contact, I have not seen one with the mech. interlock yet.

I used a pair of IEC miniature contactors with NC Aux contacts and a mechanical interlock.

2ML and 2MR are MSC # 08805251 IEC miniature contactors
Aux NC Contacts MSC # 08805210 2 Pc required
Mech. Interlock MSC # 08805798 1 Pc required

Changes to schematic:

The NC Aux contact for 2ML coil is located on 2MR and a short jumper wire back to 2ML coil.
The NC Aux contact for 2MR coil is located on 2ML and a short jumper wire back to 2MR coil.

I used parts from MSC because they order from them every day.
There are many other sources for these parts.

Bill

mcbassin · Sep 21, 2020

rdn2blazer said:
Very happy I found this thread. My Hardinge is stuck at the low rpm range. And I know nothing about electrical. I have a guy but he has never worked on this stuff I know. Are their machinery repair shops for this stuff? Looks like I will be google searching.

The first day I got my Hardinge the variable speed worked to go to a slower speed but stuck there and it has been stuck since ( a long time) I have tried trouble shooting it but don't have a clue about electrical stuff. I can hear a relay kicking when I try to lower or speed up the motor. It's as though the motor is not getting power or it's shorted? What did you end up doing to fix yours or did you get it fixed? I don't use this machine much as I have a Romi cnc Bridgeport to do my real turning on.
Any help appreciated.

thanks

donie · Sep 21, 2020

I am watching this one, I am pulling my old chucker out, putting a DRO I pulled from a junk Axelson, and get this old thing going again.

FredC · Sep 21, 2020

mcbassin said:
The first day I got my Hardinge the variable speed worked to go to a slower speed but stuck there and it has been stuck since ( a long time) I have tried trouble shooting it but don't have a clue about electrical stuff. I can hear a relay kicking when I try to lower or speed up the motor. It's as though the motor is not getting power or it's shorted? What did you end up doing to fix yours or did you get it fixed? I don't use this machine much as I have a Romi cnc Bridgeport to do my real turning on.
Any help appreciated.

thanks

When this happens on the first day I suspect the 3 phase is running backwards. Is you forward and reverse lever indicating correctly? Could be a previous owner swapped leads to correct it.
What happens on a HLV-H is the speed will run towards the opposite direction when you try to change it. There is a micro switch that keeps the speed change from jamming up. With the phase incorrect it runs to the wrong micro switch and locks up. If this is the case you need to switch lines X and Y at the plug or L1 and L2 in the cabinet then manually turn the speed screw off the locked up position. After swapping leads and unjamming the screw it should act normally unless the fuse is blown. The HC is so similar the way the varidrive works I expect it will act exactly like the HLV-H if the phasing is wrong. Someone not knowing what they are doing could swap directions on individual functions (spindle and oil pump) instead of swapping plug leads or the incoming leads L1 and L2.

If phasing was all correct when the problem started and everything was working, maybe the limit micro switch failed and it is jammed?

donie · Sep 21, 2020

Yes! if the machine is out of phase, the screw that adjust the variable pulleys, will over travel and the machine will stay at one speed. The screw needs to be returned past the stop switch by hand. Then the wires shifted.

mcbassin · Sep 22, 2020

FredC said:
When this happens on the first day I suspect the 3 phase is running backwards. Is you forward and reverse lever indicating correctly? Could be a previous owner swapped leads to correct it.
What happens on a HLV-H is the speed will run towards the opposite direction when you try to change it. There is a micro switch that keeps the speed change from jamming up. With the phase incorrect it runs to the wrong micro switch and locks up. If this is the case you need to switch lines X and Y at the plug or L1 and L2 in the cabinet then manually turn the speed screw off the locked up position. After swapping leads and unjamming the screw it should act normally unless the fuse is blown. The HC is so similar the way the varidrive works I expect it will act exactly like the HLV-H if the phasing is wrong. Someone not knowing what they are doing could swap directions on individual functions (spindle and oil pump) instead of swapping plug leads or the incoming leads L1 and L2.

If phasing was all correct when the problem started and everything was working, maybe the limit micro switch failed and it is jammed?

Thank you for the reply. I checked the micro switches inside the terminal box. The cam never made it to the roller so I don't think it's over travel. Also, the rotation seems to be fine on the spindle. I can check that this evening. I did notice while I had the cover off the wires look very old and brittle going into the motor. I'm wondering if it's shorted? Is there a fuse or circuit breaker for the variable motor?
One more question: Does anyone have a mechanical drawing(s) of this variable drive? I have no idea how to disassemble this mechanism.
thanks,
Michael

donie · Sep 22, 2020

What part of VS drive do you want to disassemble?

mcbassin · Sep 22, 2020

donie said:
What part of VS drive do you want to disassemble?

I want to pull the electric motor out to inspect the internal wires. This machine is probably a late 70s early 80s? I'm worried the wiring is causing the issue. I snagged this photo online. It is what my variable speed box looks like.

donie · Sep 22, 2020

Problem maybe to get belt in mid position, then push pulley shaft in, or pull out?
I am currently needing to replace belts, for the 2nd time after buying the machine 20yrs ago, so I have cut them off.

mcbassin · Sep 23, 2020

donie said:
Problem maybe to get belt in mid position, then push pulley shaft in, or pull out?
I am currently needing to replace belts, for the 2nd time after buying the machine 20yrs ago, so I have cut them off.

Thank you for the response. I was able to disassemble the variable assembly last night.

I think I may have found the problem. I believe the motor is shorted in the windings. The wire leads for the motor were very brittle. The insulation flaked off when I touched it basically. I tried to repair it using clear heat shrink and RTV, but apparently it's inside the windings?
Does anyone know where to find this winding assembly? or possibly where I can get it rewound?
Thank you.

metal-ica · Oct 29, 2020

I find myself dealing with this issue.

We moved some equipment around and ended up with the Hardige out of phase and spindle speed stuck on low.

I switched the terminals and removed the engaged limit switch.

Both contactors engage when switching between low and high but the spindle speed doesn't move.

All fuses appear to be good.

What am I missing?

FredC · Oct 29, 2020

If the electrics were reversed, the gearbox/screw may be jammed. My one experience (in a machine I looked at to buy) with this I turned the screw manually by hand to get it free and off the switch. You do not want to turn the screw too much by hand as the spindle needs to be running. If being jammed is the problem turn it a little with the machine off, start the spindle, turn it off and repeat till you can get the switch back in.
There can be other causes, just this one is probable after moving the machine to another outlet.

jpeter56 · Feb 10, 2022

I want to thank everyone who contributed to this thread, especially fredc and donie.
This was exactly what got my HC back up and running after a move and a backwards polarity outlet.
It was like a poltergeist got into the speed controller.
Best wishes gentlemen.
JP

scottbaer · Sep 17, 2022

hitandmiss said:
Hardinge HC troubleshooting info for variable speed change problems

Over the years several people have had problems with the HC variable speed unit that will not change speed properly.
The main problem starts with the electrical drawings are never with the machines and appear to be hard to find.
Coupled with a couple of not so obvious flaws that lead to very unexpected results see ****CAUTION**** below when trying to work on one of these with no prints.

The schematic shown here is from CHB-8220. It is an early print from 1980.
The info shown should be close enough to trouble shoot speed control problems.
View attachment 221847

Component identification:

1DS Closed when spindle is running.
SS3 Selector switch to turn variable speed on or off.
2LS Limit switch to stop speed change motor when at end of travel.
2MR Contactor to run speed change motor to raise speed.
2ML Contactor to run speed change motor to lower speed.
2CR Plug in relay to control 2MR.
3CR Plug in relay to control 2ML.
View attachment 221851

Spindle must be running and SS3 turned on to change speed.
If speed is at maximum or minimum either 2 CR or 3CR will be pulled in, these relays are plug in and can be switched.
If the same problem persists, the next thing to check is the transistors located in the speed control station.
They are in sockets and can be switched. The top one operates 2CR for increasing speed. The lower one operates 3CR for lowering speed. If the attached relay is always on, the transistor is probably shorted E to C.

*** CAUTION**** Be advised, before manually operating either 2MR or 2ML, remove 2CR and 3CR. There is no manual or electrical interlocks for 2MR or 2ML and they can both be closed at the same time and cause real problems. If the speed is stuck at either limit, the appropriate contactor will have power as soon as you jog off the limit, and if you are holding the other one in, it gets ugly fast!

If the speed is midway and not able to be changed, see below picture:

View attachment 221852

The small transformer at the lower left should have 115-120 Volts between wires 8 and 20 (the lower terminals).

The complete print is here:

View attachment 221853

Bill

Wow, under "go advanced" when editing, you can edit the thread title, but it doesn't seem to update on the forum every time.

Bill, could take picture of your schematic and send it to my email?

hitandmiss · Sep 30, 2022

Scott.
Just click on the view attachment links, or go to the first post in this thread, you can view or print what you want.
also see my Nov 26, 2018 post.

Bill

hitandmiss · Dec 14, 2022

Here's the pdf link on Babinmachine.com if anyone needs it:

http://www.babinmachine.com/PDF/Hardinge HC maintenance manual, new style.pdf

Hardinge HC spindle variable speed won't change speed troubleshooting info

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