Cunliffe Mill Electrical Problems

just another anomaly i saw when re-looking at the pictures,
i noticed on the second OL you removed as a comparison unit, the right side heater on that OL seems to have had some trauma to it as well. it is visibly "bluer" than the other 2 heaters. it may be indicative of the mills past problems.
if the heater still functions that's great,
but, we can no longer trust that the questionable OL heaters in either OL relay will operate with the same resistance as the other heaters.
When heaters overheat, their chemistry changes ever so slightly.

they become more resistant to electrical flow, which in turn creates heat.
the heat in the circuit increases the amperage necessary to complete the work of the resistant circuit.
After too many overheats, the heaters become extremely resistant to electrical flow and heat up even more as a result, ad infinitum, all the way to the point of failure.
 
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Brain Coral said:
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
Click to expand...


Sounds good to me too!!
Enjoy the relaxation!!!
I think I'll join you in a long distance beer!!!
:drinkingbeer:
Cheers!
mike:))
 
Back again... :)

I re-installed the relays and did a test run, but it's still acting the same. I gave it some thought and it occured to me that if the contactor works as it should and the motor fires right up in the Low speed setting, then the relay must be working properly, so I'm leaning towards the switch itself... perhaps one of the contacts in the switch is worn out or burnt. I haven't ruled out the possibility that there might be something wrong with the windings, but I think that I should have a good look at the switch first.

Brian :)
 
I concur, if it still acts the same we didn't find the problem.

we may have something mis-wired in the delta circuit (high speed) or a malfunctioning switch.

i really don't think you have a winding problem,
just to start the motor in the wye configuration(low speed),
motor terminals U1,V1,W1 are all connected together(shorted),
power is fed directly to motor terminals U2,V2,W2 .
if any one of the low speed windings were burned out, you would get the single phase condition of loud noise and extreme hard starting. we don't have that condition.
there are no additional windings to the motor we only have 3 sets.
all windings were utilized to run the motor in low speed
through osmosis we determine wye windings are satisfactory. most likely the motor is ok
I'll make that assumption for sake of argument at this point.

what does change is how the motor is wired to run in the Delta configuration
motor terminals U1,V1,W1, are supplied line voltage and U2,V2,W2 are connected (shorted) together.

There is another way of wiring the motor too,

for low speed operation:
Line 1(L1) is connected to motor terminal T1
L2 is connected to motor terminal T2
L3 is connected to motor terminal T3
Motor terminals T4,T5,T6 are left open(not connected to the motor circuit- allows only low speed operation on 1/2 of windings)

for high speed operation
L1 connects to T6
L2 connects to T4
L3 connects to T5
motor terminals T1,T2,T3 are shorted(connected together)- allows operation of high speed only in Delta configuration- all windings are being used.

all this as food for thought.

there may be others that may be able to add additional inspiration or if nothing else a tip or 2.
 
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Hey brian a friend of mine asked me to rewire his cunliffe mill a few months back as someone had made an attempt to do it a few years back and never finished it they just ripped out everything as it stands I have the power traverse and coolant pump running but I'm having problems with the spindle motor also from what I gather from testing the motor it has two separate windings for high and low speed if you check the high low changeover switch and take a photo of the connections I can compare it for you as this was the only part of the wiring left intact on the machine
 
Hello Mike :)

If the mill that you are working on is the same as mine, you'll agree that getting a good pic of the switch wiring is difficult, to say the least.... I am quite sick with the flue at the moment, but I will try to get down to the shop and take a picture this afternoon...

Brian
 
Brain Coral said:
Hello Mike :)

If the mill that you are working on is the same as mine, you'll agree that getting a good pic of the switch wiring is difficult, to say the least.... I am quite sick with the flue at the moment, but I will try to get down to the shop and take a picture this afternoon...

Brian
Click to expand...
I found the easiest way is to just rip the switch out the end of the knob on the switch health a hole with a flat head screw undo this and remove the knob and remove the screws on the lebel plate behind this is two more countersunk screws which have nuts on the far end of the switch once these are undone the switch will come out takes approx 3 mins have you managed to get both speeds to run on the mill yet
 
Hello Mike :)

You need to practice some punctuation, dude... ;)

I was able to power up the high speed setting of the motor only briefly, then the contactor would kick out. At testing, the amperage readings of the inrush, reached nearly 150 amps... :eek 2:

I didn't feel well enough to tinker with the switch today. I'll have a go at it in a couple of days.

Cheers... :)

Brian
 
Ya I know my English writing is terrible. I wouldn't worry too much about inrush current a motor can draw up to ten times its full load current on start up. Can I ask what horsepower your convertor is. the problem I am having with my buddy's one is that when I try and start the spindle motor the voltage collapses and the idle motor in the convertor stops briefly. He has a 15hp convertor

Regards
mike
 
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