[t-runner]

i have a kitamura S-12 and yesterday i went to start the spindle and it turned a few degrees then instantly throw a alarm. no alarm on the screen but on the spindle drive board l.e.d. #2 was on which said over current/ field loss.

Where do i start testing, is it the drive the amplifier or the motor, and how do i test?

who repairs these boards or motors in the so cal area?

the servo drive number is A06B-6041-H103
and a fanuc model 3 DC spindle.

Please help

[nsdjole]

Hello
Check armature voltage on between J and K, must have between 30V and 200V DC

Pages from DC SPINDLE SERVO UNIT.pdf
b.t.w. we repair that kind of equipments, but in wrong area of the world.
regards and good luck
djordje

[t-runner]

i will get that voltage and get back to you. Thank you i am really stuck on this and dont have the money to commit to $100 an hour plus drive time for a tech to come out. and spend a few hours then say i need a $1500 board. i got this machine for $200 and just do this for fun at home even though i run them all day at work.

[t-runner]

Volts between j and k is 8.9v dc

[Al_The_Man]

Volts between j and k is 8.9v dc

Too low, lift the wires J & K and see if the voltage comes back up?
Check resistance across J & K field.
Al.

[t-runner]

i believe the resistance was 244 ohms not k just 244.

[t-runner]

and i was hoping you would chim in al the man

[t-runner]

also when do i check the voltage just when the machine is on?

or try to turn the spindle on and then check it with it alarmed out?


and when yu say across j and k feild do you mean on screw them and check ohms on motor side? cause the 244 is with them in place down.

[Al_The_Man]

It sounds like your field supply has a problem, test voltage on J & K when non-connected to the fileld?
But the resistance sounds right so it looks like a problem with the supply?
Al.

[t-runner]

ok with j&k disconnected from the board. and measuring the board side i get

78 volt D.C.

and on the wire side 0v d.c. and 3.4 ohms

[Al_The_Man]

If the field is measuring 3.4 ohms, that sounds way too low?
I don't remember what it should be from memory, unless I find my notes?
Al.

[t-runner]

ok so if that is low what does that mean?

where do j & k go to? the spindle motor? what do they do. are they the power wires?

[neilw20]

If field is that low in resistance, the motor is most likely faulty.

[t-runner]

i have no idea why but in the back of my mind i just felt like the motor was bad.

how do i test the fanuc model 3 d.c. motor.

thank you everyone i have been trying to figure this out for awhile and progress makes me feel much better.

[neilw20]

If it has 244 ohms feeding it I would expect the field resistance to be between 100 and 400 ohms.
Probably has shorted turns. If you can find a similar motor measure it, and also the inductance of the winding.
I used the inductance method to prove a motor was faulty last week, by comparing with a good one.

[t-runner]

how do i test inductance?

[neilw20]

With a slightly fancy multimeter that measures inductance.
You will pay a bit extra for one with that feature. It wall also measure capacitance, and very low ohms.
A low cost one under $10 like this won't do it !!
Digital LCD Multimeter Voltmeter Ohm Volt Tester 830 XL | eBay

You need something like this: They start at about $20.
LCR Inductance Capacitance Digital Multimeter Meter RCL | eBay

[t-runner]

how do i measure that across the windings? i know alot of questions. sorry i just dont want to do it wrong and rule something out if im not sure.


also a tech told me field side of j to k should be about 3.8 ohms?

[neilw20]

Sorry I looked more closely at the circuit.
As stated in post #2 range of 30 - 200v DC is to be expected, but if it is tripping out, then it is rather hard to measure when it has gone off.!!
3.8 ohms means current would be between 8A and 52A
The current sense resistor is 0.2ohm/20W so the maximum current is below 10A
sqrt(20/.2)
If resistance is 3.8 ohms max voltage is about 35v. About 350W
Input fuse (F4) is 5A, giving a max input of 1KW.
Based on the above, 3.8 ohms sounds reasonable.

To get some indication you need to be able to measure the peak voltage across the current sense resistor RCD, terminals CDD and CDC as the units trips and fails.

If the power remains on, (AC voltage - maybe 30vAC) across terminals 7 and 8 of transformer, and there is no voltage on JK then the SCR and diodes will more than likely be OK

You might need to check the diodes and SCRs D1,D2 and SCR13 and SCR14

I believe you have a problem in the control circuit

Can you get it to run at low speed?

[Al_The_Man]

If this motor has not had preventative maintenance for a while, I suggest stripping it down and do an overhaul, I have seen everything from worn brushes, carbon build up, to thrown com solder on these motors.
I could not find my notes on the readings taken on previous tests, unfortunately.
Al.