Dual speed motor on Hardinge HLV-H - Fast not working

This is a lathe renovation project of mine I have started. The Fast speed setting for dual speed lever does not work. Slow speed setting works fine and accelerate/decelerate works fine. However when I move the lever to Neutral then  on to Fast the power to the motor trips off. If I then keep the lever in Fast and pull the power mushroom on the control panel above the headstock to On, the motor emits a horrible cacophony like a mixture of a gravel grinder and a faulty starter motor solenoid on an old car that is not engaging and not turning over properly, meanwhile the spindle jogs around very unevenly. What do you think is going on and what can I do to remedy it? I am using a rotary converter 3 -phase feed which is rated in excess of the power draw.

Edited By Adam Harris on 30/04/2019 22:52:47

Edited By Adam Harris on 30/04/2019 22:53:15

The dual speed main motor is 1.1 kw on Fast wiring circuit (0.35 kw on Slow circuit). The Rotary Converter is 2.2kw with a maximum power for any one motor it is feeding of 1.1kw, so should be good for this motor shouldn't it?

Edited By Adam Harris on 01/05/2019 00:20:17

My HLV motor had two separate windings for fast and slow, I don't know if the HLV-H is the same but if it is I would inspect inside the motor junction box to see that none are loose or shorting to the frame. Mine was a Feltham machine with a Newman Industries motor on it, and had a wiring schematic on the inside cover of the motor.

Hi it sounds like it may be single phasing which may be caused by a bad contactor, a loose wire, or a faulty winding in the motor fail it needs a thorough checking with a meter and a wireing diagram would help.

David

Before you get too far into the internal working it would be worth rotating the phase connections to the lathe. Under some conditions the generated phases from the converter will drop in voltage and any contactors will drop out until the voltage comes back up and then the motor current draw causes the voltage to drop once again. A self perpetuating 'fault' condition with associated cacophony!

Move all 3 input phase wires round in the same direction once and try again. If that doesn't work then continue to move the wires round one further step in the same direction. If one of these setups works then all well and good. If none do, then a deeper investigation is required.

When I ran a small workshop we had a few of these machines and from your description of the noise i would almost guarantee that your motor is missing a phase in the high setting.

Our maintenance man would get on the job immediately and generally had it fixed in less than 30 minutes.

It was almost always a dirty connection and a good clean soon fixed it.

Thank you everyone - I will check for loose/dirty connections at the motor and at any contactors, and thank you Swarf Maker I will test rotating the 3 feed wires around. Will revert with results. Sadly. I do not have an electrical wiring diagram.

By the way , my rotary converter does not have any individual motor restriction of 1.1kw (error in my original posting) and since it is not the converter itself that is tripping I am assuming the converter must be good.

At least not specifically stated, but apparently all converters do have a limit for individual motors as part of their design, and in my case 2.2kw converter likely has an individual motor limit of 1.5kw which is still in excess of power needed

Swarf Maker you are brilliant!!! Rotated around and found the positions that work! All running like a dream - very many thanks. Adam

Edited By Adam Harris on 01/05/2019 15:45:41