HLV-kl1 electrical fault with feed motor

Floodworks · Jan 2, 2021

Hi Everyone,

My carriage feed motor is not working. When I first switched the machine on after buying it in August, the motor ran for about 3 seconds then stopped (I had it sitting on the drip tray, disconnected from the carriage). First I found The 2amp fuse conecting two black wires that run to the feed control box was blown on the main board. I also found there's continuity between Earth and the blue and brown wires going to the diode assembly which I assume is some sort of rectifier. I traced this short back to the transformer and there seems to be a short between several of the wires coming out of the transformer and EARTH. There is a small "shadow" of soot surrounding the transformer where it is mounted onto the backing plate.

Anyone have any ideas what might be wrong? Electronics is not my strongest subject but I'm learning.

Many Thanks in advance

Alex

Billtodd · Jan 3, 2021

Youll need to check further . Don't Panic!

uk wired hlvhs have an isolaing transformer to drop the 415 3ph to 240v or 110v for the control and one side of this is taken to chassis,.hence your apparent short to earth (perhaps!).

It's not uncommon to have failed rectifiers and variac but first check for shorts to chassis around the bakelite insulators, brush holders, fuse holders etc. Etc.

The soot shadow may not be significant, the wiper brush can generate some grime in normal use.

Hardinge HLV-H 397 Wiring Diagram.pdf - Google Drive

Bill

Peter. · Jan 3, 2021

Bill I think you have an error in that diagram. Moving the left/stop/right switch will put a short across the diode output if I'm reading it right.

Billtodd · Jan 3, 2021

The way the switch works is like four spst buttons, so switching right only connects one pair and left the other pair. In the centre, the motor IS shorted via the two braking resistors.

Granted the diagram could be confusing, but essentially only the upper pair or lower pair of contacts are moved when switching left or right .so there is no actual short circuit.

Ill try and redraw the diagram to make it clearer :-)

Peter. · Jan 3, 2021

Floodworks said:
Hi Everyone,

My carriage feed motor is not working. When I first switched the machine on after buying it in August, the motor ran for about 3 seconds then stopped (I had it sitting on the drip tray, disconnected from the carriage). First I found The 2amp fuse conecting two black wires that run to the feed control box was blown on the main board. I also found there's continuity between Earth and the blue and brown wires going to the diode assembly which I assume is some sort of rectifier. I traced this short back to the transformer and there seems to be a short between several of the wires coming out of the transformer and EARTH. There is a small "shadow" of soot surrounding the transformer where it is mounted onto the backing plate.

Anyone have any ideas what might be wrong? Electronics is not my strongest subject but I'm learning.

Many Thanks in advance

Alex

Alex, as Bill said don't panic. So long as your motor is ok and the variac isn't faulty it's not going to cost a whole bunch to remedy your issue. Even if you've blown a field coil I have a spare here somewhere.

The transformer which has the soot around it - where is it? Do you mean the step-down unit that drops the supply voltage to the variac, or do you mean the variac iteslf?

Peter. · Jan 3, 2021

Billtodd said:
The way the switch works is like four spst buttons, so switching right only connects one pair and left the other pair. In the centre, the motor IS shorted via the two braking resistors.

Granted the diagram could be confusing, but essentially only the upper pair or lower pair of contacts are moved when switching left or right .so there is no actual short circuit.

Ill try and redraw the diagram to make it clearer :-)

I knew it would be me reading it incorrectly. I imagined the four contacts moving upwards together or downwards together.

Floodworks · Jan 3, 2021

Billtodd said:
Youll need to check further . Don't Panic!

uk wired hlvhs have an isolaing transformer to drop the 415 3ph to 240v or 110v for the control and one side of this is taken to chassis,.hence your apparent short to earth (perhaps!).

It's not uncommon to have failed rectifiers and variac but first check for shorts to chassis around the bakelite insulators, brush holders, fuse holders etc. Etc.

The soot shadow may not be significant, the wiper brush can generate some grime in normal use.

Hardinge HLV-H 397 Wiring Diagram.pdf - Google Drive

Bill

Hi Bill,

Many thanks for your reply.

I checked for shorts to the chassis from all parts on the motor and it all seems good. The short is occurring before the diodes and variac. The variac itself looks very clean, the soot i mentioned is surrounding the step down transformer in the main circuit cabinet at the headstock end of the machine.
How would I know if a diode had failed? I checked them with the diode feature on my multimeter and they all only gave a reading in only one direction, so they all seem good, they look clean too.

Two of the output cables from the transformer labled 8 and x8 are bolted to the chassis, as you suggest, so it would make sense that these have continuity with earth. However, most of the outputs from the transformer are also shorting with the chassis, this seems wrong to me?! It is a second one of these x8 cables, along with another labled x9 (whose source I havent been able to track down yet) supply the power to the motor speed control box at the tailstock end of the machine. Ive attached a couple of photos below

It just occurred to me that the spindle brake also doesn't seem to be working, and I havent tested the pump... I'll do that tomorrow. So maybe there is a fault with the main transformer.

Floodworks · Jan 3, 2021

HI Peter,

Thanks for the reassurances. The soot is on the board that the main step down transformer is mounted to. There's not a load of it, just a bit of a "shadow", you might be able to just pick it out in the photos I posted above.

Floodworks · Jan 3, 2021

Billtodd said:
Youll need to check further . Don't Panic!

uk wired hlvhs have an isolaing transformer to drop the 415 3ph to 240v or 110v for the control and one side of this is taken to chassis,.hence your apparent short to earth (perhaps!).

It's not uncommon to have failed rectifiers and variac but first check for shorts to chassis around the bakelite insulators, brush holders, fuse holders etc. Etc.

The soot shadow may not be significant, the wiper brush can generate some grime in normal use.

Hardinge HLV-H 397 Wiring Diagram.pdf - Google Drive

Bill

Oh that's weird, I just wrote a response but for some reason it didn't send. Guess I'll write it again!

Thanks for your response Bill.

Looking at the main step down transformer, I've got two cables coming out (labled 8, X8) that bolt to the chassis, like you mentioned.
There's also a second X8 which supplies the power to feed motor control box at the back of the machine, along with another cable labled X9, whose origin I havent managed to track down yet. Does this seem right. I tested all of the other ouputs on the transformer and they all except one short to the chassis- this doesnt seem right?!

Everything in the speed control box looks clean and tidy, the diodes all seem to be good as does the variac- very clean. I'm confident it is not anything at this end causing the a short.

It also just occurred to me that the spindle brake doesnt seem to be working, and as I'm yet to test the coolant pump that may well be down as well, indicating something wrong with the main transformer? I'll look into this more tomorrow. I'll also cross reference averything off of the diagram- thankyou for posting that.

I've attached a couple of pics of the wiring cabinet.

Billtodd · Jan 3, 2021

The transformer looks fine and probably smells fine , so unlikely to be the problem . A nose is a useful diagnostic tool :-)

The brake is powered from either the main Hi/Low speed lever switch (the red wires) or from the control pod 'brake off' switch (power on to the brake contactor -> solenoid pulls the brake off BTW) so if the fuse has failed to the power feed it'll likely not feed the brake or speed jack.

Be very careful if you have 415 3ph into the machine while fiddling . If you are unsure about what you're doing , don't do it!

You can be easily fooled by digital multimeters : a good mains test lamp is often a better indicator of bad connections etc. Lots of things will look like a short to chassis! Make sure you isolate both feed and return before assuming there's some internal short.

Might be worth checking behind the fuse holders for arcing to chassis (condensation can form behind them and start a slow failure) , Similarly , brush holders in the DC motor have burned and shorted.

Don't assume the worst - If it ain't black and charred it's probably OK

Peter from Holland · Jan 4, 2021

This is a KL1 isn`t it
They have a different electrical diagram as a HLV
If you send me a PM I can e-mail you one
The shop I got it from did not answer my question if I could make it public So I will not But I will forward it to anyone

Peter

Floodworks · Jan 4, 2021

I just found that the 4a Fuse F1 is blown, just ordered a new one...

fuse holder and behind looks clean, no condensation

I have opened the motor and there is no continuity between the two cables going in and ouut of the field coil... This means the coil is bust right?

Peter. · Jan 4, 2021

Floodworks said:
I just found that the 4a Fuse F1 is blown, just ordered a new one...

fuse holder and behind looks clean, no condensation

I have opened the motor and there is no continuity between the two cables going in and ouut of the field coil... This means the coil is bust right?

There should be continuity. You'll have to carefully open up the motor and see if there's an obvious fault. If you're lucky it might be the link wire.

Billtodd · Jan 4, 2021

An open circuit stator might well cause the fuse to blow.

Check the cable to the motor , it gets bent back and forth so is most likely to fail. If the wire seems ok , give it a good tugging to check for intermittent faults.

If the cable checks out, as Peter suggests above, open the motor and check for obvious broken wires . The motors are usually well made and quite robust so expect loose connection rather than burn out . Especially as the diode bridges seem ok.

Floodworks · Jan 25, 2021

Back again..

All is good with the wiring leading up to the motor. I opened the motor up itself and it seems, though I might be wrong, that the field windings are bust. There is no continuity between the two ends of the windings. The strange thing is, I probed the connecting wire that joins the two windings together, and get no continuity between this centre point and either end of the circuit, so this seems to imply both windings are broken?! I wonder what the best way to fix this is. Can I get replacement windings anywhere or will I have to make them myself?

Floodworks · Jan 25, 2021

Actually maybe I'm just being an idiot. I measured the resistance of the coils (on the 2000ohm setting, not the continuity setting) and I got a reading of 1800 ohm which corresponds to the correct resistance of the good coil this guy had on his HLV-h

Hardinge HLV Part 3: Feed Motor | A Blog Devoted to my Many Hobbies

This is a good resource for anyone wanting to wind their own coils by the way!

Maybe they are good after all, I'm going to put everything back together and replace the blown fuse in the board and see if I'm fussing over nothing.

Floodworks · Jan 29, 2021

I just put the motor back together, with all the fuses in the board replaced, and the feed ran on slow for a few seconds. It was faster running forward than running backward. As I ramped up the speed the 2a Fuse blew and it died. I repeated the procedure, ran it for longer on the slow speed and then as I increased it again the same thing happened. It's the fuse on the brush circuit that blew.

Billtodd · Jan 29, 2021

Take the back of the motor off (can be done with out removing motor) and inspect the brush holders for arcing to the metal body .
Bill

Stradbash · Jan 29, 2021

Billtodd said:
Take the back of the motor off (can be done with out removing motor) and inspect the brush holders for arcing to the metal body .
Bill

That’s good advice! I know my brush holders were trashed.

Sent from my iPhone using Tapatalk

Peter. · Jan 29, 2021

Good shout Bill. I'm pretty sure my brush holders were only held in place by a grub screw.

HLV-kl1 electrical fault with feed motor

Plastic

Titanium

Attachments

Titanium

Titanium

Titanium

Titanium

Plastic

Plastic

Plastic

Titanium

Diamond

Plastic

Titanium

Titanium

Plastic

Plastic

Plastic

Titanium

Cast Iron

Titanium

Similar threads