Have a Bridgeport with TNC 151B controller and the spindle doesn’t work.

All signals coming from control are good but the problem is the MTI-1 board keeps blowing fuses. We checked the board and everything visually looks OK and measuring all caps, diodes and transformer seem to measure OK. We even tried disconnecting the Spindle field and armature wires but still the fuse blows.

At this point we figure the board is bad and are looking to send it out for repair or replace it (if anyone has a source please share) but we worry that there might be a problem with another one of the boards or spindle.

Anyone have any advise on this problem??

Dear all

I have a bridgeport vmc-500/16digital m/c with Heidenhain TNC410MA controller.Presantly we are facing aproblems regarding POWER FAIL message.

when we start the m/c system is booting completely but at the time of m/c ON system gives a message "POWERFAIL" & drive is not ready.

we have checked +24v supply found ok.

Pl. help me how to solve this problems.

with regards,

Shailesh

was this machine previously running in this location?

is the message "POWER INTERRUPTED"?

Should have said that all the axes run fine. Control powers up 100% just the spindle doesn't work and its the MTI-1 board that blows fuses every time as soon as it gets power. Do you have any part sources?

It ended up being the varistor on the MTI-1 board. It's jumpered right now until I can find a replacement.

So does anyone know where to find a Varistor marked Z-440G?? or a cross refrenced replacement?

I've had a good look for these varistors before.
I had one blow on a Markon BL105 5kVA Generator Alternator.
I didn't even know that this was a varistor.
So for the sake of this mystery article i had to dismantle an 'out of service' unit and swap the varistor across.
A year on and a search turned up this:
Z440G THERM LEAD VAR 20MMD 484VRMS 685VV 900MW Z440G Runout Product Texim Europe
That sounds like what you'd expect
So that's a 20mm diameter round component which can happily exist at 484vrms and can dispose of 900milliwatt in transients. I assume.
I'm a bit puzzled whn you say that now the duff varistor is jumpered.
To my understanding [which is likely to be flawed] a varistor is intended to do nothing [not conduct] in normal operation and conducts momentarily when exposed to very high voltages - transients.
So then when a varistor blows you can generally return the circuit to normal operation by cutting it out.
But if you jumper it or short it out then you would generally have jumpered the component that it protects - in the case of my alternator this is a 16amp 1200V diode on the rotor.
I assume that if I cut a duff varistor out of this circuit then I just don't have the transient protection that it offers. Which may or may not be critical, depending how much work it generally does.
Please can someone let me know if I have got this completely wrong!!

I am having problems getting the spindle drive to run also, I was told the transformers had problems. I was back trying to get the darn thing to work today and had it under power and stepped away for a few minutes, came back to some very burnt components on the MT1-1 board, is the varistor your refering to the big round disc beside the orange wiring block? any help guys, thanks.

Sounds likes its time to dump the DC system and upgrade to AC.

I have an interact 4 that i bought 2 years ago and retrofited to a centroid.......I wanted to get away from the DC system because you cant get parts are they are way too expensive.......I fitted a 10 HP AC marathon Micromax motor and 10 HP flux fector VFD drive into the machine. It works GREAT and have had no problems for 2 years. I dont know how much work it would be to hook up an AC system to the control and have it work correct but it would be a good rewarding project. The bridgeport Series 2 Interact 4 is a hell of a machine....It just needs a better control. The Ajax/Centroid control works great. I have had 2 of them and the retrofits were simple.

Just thought i would give you guys my 2 cents about keeping your machine running trouble free.