Cunliffe Mill Electrical Problems

[Ulma Doctor]

working without a diagram is like riding a unicycle on a basketball in long distance troubleshooting!:jester:

 

[Brain Coral]

I agree... I wish that I had one. There likely was one on the inside of the cabinet door, but it has gone like the powdered rubber gasket door seal...

Unless I have something specific to look for, I will do some careful investigating. I might not be up on electrical problems, but I am careful and meticulous and will not go beyond what I can put back together.

I am off to bed for an early start to my week. Thanks for all of your help, Mike

Brian

 

[Ulma Doctor]

i'll stick with you Brian, there are things that would take me seconds to figure out if i were there. but i'm happy to help the hard way )!!!
i'm still thinking wye start/run low/, delta-high speed kinda like this

http://apps.motorboss.com/connections/3226.pdf

we can check out the motor windings, test switches, test wiring, test overload relays and contactor coils whatever is necessary!

Where would you like to start?
i'd start with the high speed overload relay and go from there . ohm check pole for pole to see if all poles have continuity.
test overload circuit interrupt terminals - they should be normally closed- if they are open the contactor may drop out.
if the overload has removeable heaters remove them and ohm test them too!

no worries we'll get it tickin' soon enough.
we can get into other things later

no need to say thanks yet,
you can say thanks to all who help out getting her running- when she's running again!!!!
cheers, and good night sir
m)

 

[Brain Coral]

Hello again Mike

I haven't checked in on this thread for a few days and didn't see your reply until now. I have been working on a couple of kitchen cabinets for a client and have all of my metalworking machinery all covered up with tarps.

I've tried starting the mill at high speed a couple more times, after cleaning the contactors, but it drops the contactor out every time. I did notice, with the motor hanging out of the back, that it "growls" a little when starting up at high speed, but not at low speed.

Looking at the pics of the panel, where would I find the high speed overload relay and also the overload circuit interrupt terminals ?

Thanks...

Brian

 

[Ulma Doctor]

Hi Brian,
i think the OL relay is the larger black box at the bottom of the control panel.
this item either comes apart where it sits, but may have to be removed to disassemble.
try to do it the easy way first, in the machine...
there is a most likely 3 coils or heaters as they are called, inside of the OL relay.
visual inspection can often see any suspect overheating or open coils
an ohm test would confirm their serviceability. you would test the interrupt terminals on the same OL relay sometimes marked #'s 95 and 96

in the off chance the OL relay doesn't have removable heaters or is found faulty, replacement would be necessary.


mike)

 

[Brain Coral]

Hello Mike,

This is a start... I think that this is what you were looking for...





This is the method that I used to test it. Is this correct ?





I don't have a handle on all of the jargon and I don't understand the interrupt relays... ?

I have company coming for supper, so I'll have to leave this until tomorrow morning...

Brian

 

[Ulma Doctor]

Hello Mike,
This is a start... I think that this is what you were looking for...
This is the method that I used to test it. Is this correct ?

I don't have a handle on all of the jargon and I don't understand the interrupt relays... ?

I have company coming for supper, so I'll have to leave this until tomorrow morning...

Brian

Hi Brian,
that is an OL relay, yes sir!!!
I don't like the looks of the heater coil on the right side, if you look at the heater coil the inner coil appears to be touching the outer coil or are very close to touching and could be a factor in the shut down condition.:thinking:

(i'm assuming you have already disconnected power to the mill)
I am curious also to look inside the little box situated below this OL relay, the one labeled " Danger live Terminals".
if you disconnect the power from the milling machine to the RPC you won't be in danger to remove the cover mentioned above that conceals the guts of the larger black box. there appears to be a dial or knob missing- that throws up a red flag for me...

Yes Brian, you will test each terminal exactly as pictured on the Rx1 setting(lowest ohm setting for low resistance circuits). you should read very little resistance or no resistance dependent on the sensitivity of your meter on each set of terminals.
the interrupt circuit is the 2 smaller terminals pictured on the left side of the OL relay.
by putting a meter leads on both of the smaller stacked screw terminals and setting the Ohm meter to Rx1(lowest setting) you can test the interrupt. the interrupt should be a normally closed switch thus there should be little or no resistance measured dependent on the sensitivity of the meter.
if this switch should happen to be open, it would need repair or replacement- it is not functioning correctly.

i'll try not to use too many technical electricalisms , let me know if i'm confusing you and i'll take it down a notch.
i make the constant mistake of thinking that others know what i know,:banghead:
(not always a good thing- there are a lot smarter people than I)
mike)

 

[Brain Coral]

Hello Mike

I'm back with a brief update. I get a Zero reading on all terminals, including the interrupt terminals. I decided to remove the other relay to compare the two and to check if the readings were the same. I realize that the other relay has nothing to do with the main motor contactor, but I just wanted to have a look while I was at it.

I adjusted the spring in all three heaters so that there is no contact at any point. The other two heaters had very close contact, if not actually touching at a couple of points in the spiral when closing the contact.

Before....



After...



Here is a pic of the other relay...



As far as the lower " Danger Live Terminals" box is concerned, there doesn't seem to be anything amiss. There is a screw missing that attaches the front cover... the bakelite housing is broken away at that corner for some reason... The spot that appears to be missing a knob, engages the lever on the door of the panel and is simply an On/Off safety switch. When turned to the On position, the lever is locked onto a cam that won't allow the door to open. I have cheated it for these pics and turned the switch to the On position with a couple of screwdrivers... NO POWER WHATSOEVER !!! to the mill, of course...













Since I've "adjusted" the heaters, should I go ahead, reinstall and try the high speed again, or should we troubleshoot some more? What kind of damage will there be to the motor with repeated attempts at starting it with one phase seeming to be missing ?

Brian

 

[Ulma Doctor]

Hi Brian,
The repaired OL looks good now after bending the coil.:thumbsup2:

The Danger Live box is simply the on off switch, I see now...i was a little perplexed by the box.


After making the repair to the OL heater, i'd re-install and go for a test run.
you'll want to set the OL to it's highest setting by pushing the indicator lever to the right(i believe it was 14Amps or 16A if memory serves) and try to fire it up once again.

Damaged windings could occur as a result of trying to start the motor with only single phase supplied, if the single phase condition was to last a long time without a breaker kicking out.
The amps would likely rise in the single phase circuit in attempting to start the motor and kick your breaker.
most likely you won't cause any more significant damage than has already been done, if there already was an existent winding issue.
just don't let the motor try to start in a stall condition for more than a couple seconds without rotor movement , you'll be OK

 

[Brain Coral]

Hello Mike,

Sounds good... I'll re-install the relays and give it a go in the morning. I'm kicking back, after a good supper and a couple of beers...

Brian