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Hardinge TM/UM Motor Issues Advice Request

Hardinge Henry

Plastic
Joined
Jan 15, 2019
Greetings

I have recently acquired a Hardinge UM Serial Number 20371 with an old (like the machine) 3 phase motor. Connected to a VFD with motor belt disconnected, the motor starter overload tripped immediately. Bypassing the starter connecting from the VFD directly to the barrel switch with no load the motor would operate forward and reverse fast and slow. With belt connected the motor would not start and tripped the house distribution panel 220 volt breaker. The shaft which connects by three belts to the spindle can be turned by hand by rotating the pulley. I removed the motor intending to test it or have it tested. It has no name/information plate and the wiring connections on the motor are not accessible. I have attached a picture of the mill and pictures of the motor.

I am seeking advice on how or whether to proceed with testing the motor and generally how to get the machine operational.

Thanks

IMG_2359.jpgIMG_2342.jpgIMG_2361.jpgIMG_2362.jpgIMG_2366.jpg
 
Had the motor tested and windings are shot. Are there feasible options other than the multiple pulley and two speed motor for speed control? Could a single phase motor be used? Any advice would be greatly appreciated.

Thanks
 
If you use a VFD do you need 2 speeds and multiple pulleys? Motor rewinders do not like to mess with small motors but I think it can be done for more money than new will cost.
You should be able to find something that will fit the base and line up on the pulley location. Motor frames and mounting are fairly standard.
 
Hello again

After searching previous posts it seems a 1 hp 3 phase 220 volt motor with a VFD is the way to go. I do still have questions on how it would be wired. Would the barrel switches be out of the system entirely? How would reverse be implemented? I have briefly looked at VFDs and many seem terse in their capabilities descriptions. Is there a recommendation for a specific VFD or a brand or source?

Thanks
 
Had the motor tested and windings are shot. Are there feasible options other than the multiple pulley and two speed motor for speed control? Could a single phase motor be used? Any advice would be greatly appreciated.
Thanks

Some comments, in no particular order:

Without a namplate you do not know the voltage the motor is designed to run. It is not impossible that the motor is
a 480 volt motor. Based on the vintage and number of wires apparent, it is probably a single voltage, two speed consequent
pole motor.

Not all motor shops are aware of how this are tested. Somebody, somewhere stated the 'windings were shot' but there
really should be more information there. Is any winding shorted to ground? Do the resistances for each winding look about
right? There should be continuity between all wires. Do you trust the motor shop, if it was a shop that tested it?

You can electrically test the motor yourself. A good dmm will give you a resistance reading from any one wire to ground. Should
be nearly infinite. Then measure from any one wire (call it T1) to all the other wires, using a range that can measure a few
ohms. You should see three different values, two the same on one pair, two the same on two other pairs, and one value for
one other wire. The motor if consequent pole can be drawn as a ring of six windings, with the connection between
each pair of wires brought out of the motor. Sketch it up and you can imagine the wiring inside the motor better.

Be sure the drum switches are correctly connected, there may be a diagram if this has the two separate drum switches
on the side in boxes.

IF it is apparent that motor really is defective, OR if it is apparent the motor is 480 volt, THEN your best approach is to probably
replace this motor with a three phase, single voltage one, of around 1 hp. Remove all the drum switches and any motor
starters or contactors or overloads or fuses or other electrical components between the motor and the VFD. They are not
required any more.

Wire the motor directly to the VFD. I've used both TECO and Hitachi types to good effect. You will be limited to around 1 hp
if you go with a 120 volt VFD, but the original motor was 3/4 or 3/8 hp depending on hi or lo speed range so you will have
ample power available with a 1 hp replacement.

The motor is now controlled completely through the VFD, you can make a small separate control box with a variable resistor
and a toggle switch to set speed and direction. Suggest you do NOT discard the drum switches as these will be valuable to
another hardinge enthusiast.
 
Hello again

After searching previous posts it seems a 1 hp 3 phase 220 volt motor with a VFD is the way to go.
If the original was 1 HP, and you expect to actually get good USE out of a VFD'ed motor, you'll need a 50% or better boost in nameplate HP so the ends of the RPM band are still useful under load, not just for demonstration.

Much the same if one were to use a DC motor and DC Drive.

Either up-size the motor and VFD or DC Drive, or keep your belted mechanical ratios. You will still need them, AC or DC at same-same OEM motor HP..

I do still have questions on how it would be wired. Would the barrel switches be out of the system entirely? How would reverse be implemented? I have briefly looked at VFDs and many seem terse in their capabilities descriptions. Is there a recommendation for a specific VFD or a brand or source?

Thanks

Either of VFD or DC Drive, one sheds all OEM controls, uses those the drive provides or provides for remoting of.-

They can be in the same LOCATION, if it is the best and safest location, but they have no electrical relationship to OEM fixed-speed wiring.

"RTFM". Both VFD and DC Drive cover all that.

Not the only way to go, but compare KB Electronics DC Drive and KB's VFD - both available in a nice NEMA 4X / IP65, even "washdown" sealed enclosures that are near-as-dammit identical as to controls.

Mount either of those on a stiff steel conduit, wire per the manual to a suitable motor, where "suitable" is "inverter duty" for AC, "rectified power" rated for DC.

AC motor will generally be smaller, lighter, lower-cost, any given HP. DC Drives outlast VFD's by 20-plus years, but DC motors (other than PM, brushless) need brush & commutator maintenance @ approx 2,000 power-on-hours, whereas a 3-P AC motor generally outlasts a human lifetime, no maintenance unless the bearings degrade.

Do the math. Used motors are low risk. Used VFD or DC Drives are higher risk. Better to buy those NEW, with warranty, either one. New doesn't cost much more than GOOD used ones anyway.


Your mill. Your call.
 
Thank you very much for your replies. I now feel much more like I can get there from here.

With regard to the existing motor, I am not confident in the shop test. I got the "windings are shot" through a brief phone conversation and there will hopefully be more information when I get the invoice and report. Regardless, I would prefer the convenience provided by a VFD for speed changes and I would not relish trouble shooting and rewiring the starter and barrel switches (there looks to be a little paper left on the inside of the barrel switch cover which is probably where a diagram was ripped out). So I am fine with replacing the motor and getting a VFD. I am curious whether you think the behavior I described in the original post would be consistent with a 480 volt motor trying to run on 220? If it is a 480 volt motor I would assume it would be of little value. Is that correct?

Are there other specifications I should be aware of for the prospective motor besides "inverter duty", 3 phase, 220 volt, single speed, AC? I read here that 1140 RPM would be better than 1750? In adjusting the motor speed and sizing the pulleys it would seem prudent not to run the spindle above the legacy/original 1850 max speed. Do you agree? Are there reasons (other than exceeding the capability of a 120 volt input VFD) not to go to a 1 1/2 hp motor?

I read in past posts (might have been you) the idea of using the barrel switch levers in the control circuit for the VFD. For example, using the FWD/OFF/REV lever for the reversing switch and using the FAST/SLOW lever as an INCREASE/DECREASE speed functions. This idea appeals to me and I may investigate options when looking at VFD capabilities and controls implementation. In particular, using the FWD/OFF/REV lever could enable continued use of the brake function. I suppose you would need to disable the brake if you used a toggle reverse switch with the VFD. Have there been any further thoughts on using these controls?

Thanks again for your help.
 
Are there other specifications I should be aware of for the prospective motor besides "inverter duty", 3 phase, 220 volt, single speed, AC?
It's a mill. Horizontal, even. Similar-sized ones built by Burke, Diamond, Nichols, et al utilized Lima, Century, or Master geared-head motors, whether just one fixed-reduction or selectable of two to four ratios, PLUS three, six, or even nine belted or roller-chain ratios.

IOW slower is better for horizontals. 8-pole Marathon Black Max or Blue Max will be hard to find, 6-pole easier, 4-pole more so, yet.

You do NOT want a 2-pole. VFD are MUCH better at over-speeding than under.

If you are into teeny-tiny Carbide endmills instead of HSS milling cutters that resemble gear wheels, what you will want is a self-powered vertical-mostly head of the "router" tribe. Serious-high RPM.

Integrating old controls to either of a VFD or DC drive is a waste of time - makes future sale or maintenance harder than it needs to be.

If you like the look, or where they are located, just put the controls the VFD or DC Drive maker WANTS in their place, "period correct" look if it floats yer boat, modern otherwise.

Those nice NEMA 4X washdown enclosures KB use? The protective liquid-tight elastomer boots for toggle switches are a commodity item, A few bucks, and you have a whole bag of 'em.

Allen-Bradley oil-proof pushbutton con-trols - "E-Stop" included -are all over the web, new, used, and copied too-damned-cheaply. Consider also a "rotary disconnect" if you want local lock-out for kid-proofing. Need only a decent sized "Bell" (cast) electrical box like an outdoor outlet, not a wall-mount panel with a massive lever.
 
If you want you can up size the motor above what a 120 volt VFD can drive. I think one hp is the clip level. Be
sure you get one that can run sensorless vector mode - the Hitachi I just put in a lathe autotunes very nicely. Goes
through a learning cycle and all.

You could employ the drum switches run by the sticks, but for ease of assembly your best bet is just a small
electrical enclosure with a one or two toggle switches and a variable resistor, linked to the drive (which would
fit nicely in the lower cabinet I suspect) with some shielded muticonductor cable.

Especially if you upsize the motor I would probably put a 1725 rpm motor in there.

You can do a simple test on the motor, as mentioned. Just need a decent DMM.
 








 
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