ST-10 Main control transformer - DEAD (2018) machine

So,

We had one of the control transformers in a 2018 haas st-10 go out (SMOKE EVERYWHERE). I am reluctant to get any replacement parts from haas, as they are expensive, and seemingly do not work or are of terrible quality. I think if you own a HAAS, or many as we do, you understand the quality/customer support train long ago left the station. I am curious if there is any reason NOT to replace this with a simple 240/120v step down control transformer? I pulled the wire looms apart all of our power is 240 and then machine just bridges this to the panel for 240 and pulls off some for the 120. I assume this od multi transformer configuration is to provide either extra power, I am unsure why they don't just use 1... Maybe a load balancing issue?

I assume they use the transformer they do to be able to use both 208 and 240 in the machines.

There also seems to be a thermal overload switch, I have not seen this in other transformers, if someone ahs experience with this i would be interested.

Part number of assembly 32-5826 2900.00 was quote
Part number of transformer 64-1459

Automation direct has what seems like a replacement for 190.00

Hopefully this can help someone else, as well as get me an answer on the thermal overload.

I looked up the Xformer .... say's XFMR 240:119V@3A CHASSIS MOUNTED
I do not know the newer machines but I've replaced and spec'd numerous Xformers in the past. Numerous options on Xformers for sure. I poked into a manual during yet another LONG zoom call (day job) :-) See below. May not even be your setup but the module picture matched. I guess I was just wondering how many inputs and how many outputs? Any centertap? keep us posted. I Love AD (automation direct) They have app engineers if you call them the will help you spec the replacement.

https://staging-diy.haascnc.com/sit...0284_Rev_H_English_January_2010.pdf?0=%3F3141

See page 24. (text below)
Primary Connection To T1
Input power to T1 is supplied through CB1, the main circuit breaker. Three-phase 230 to T1 is connected to
the first three terminals of TB10.
Circuit breaker CB1 protects the spindle drive and shuts off all power to the control. A trip of this breaker
indicates a serious overload problem and should not be reset without investigating the cause of the trip.
Main Contactor K1
Main contactor K1 is used to turn the control on and off. The Power On switch applies power to the coil of K1
and after it is energized, auxiliary contacts on K1 continue to apply power to the coil. The Power Off switch on
the front panel will always remove power from this contactor.
When the main contactor is off, the only power used by the control is supplied through two ½ amp fuses to
the circuit that activates the contactor. An overvoltage or lightning strike will blow these fuses and shut off the
main contactor.
The power to operate the main contactor is supplied from a 24V AC control transformer that is primary fused
at ½ amp. This ensures that the only circuit powered when the machine is turned off is this transformer and
only low voltage is present at the front panel on/off switches.
Voltage Selection Taps
There are four labeled plastic terminal blocks. Each block has three connections for wires labeled 74, 75, and
76. Follow the instructions printed on the transformer.
Secondary Connection To T1
The secondary output from T1 is 115V AC three-phase CB2 that protects the secondary of transformer T1 and
is rated at 25 amps.
Optional 480V Transformer
60Hz 50Hz
Input Voltage Range Tap Input Voltage Range Tap
493-510 1 (504) 423-440 1 (504)
481-492 2 (492) 412-422 2 (492)
469-480 3 (480) 401-411 3 (480)
457-468 4 (468) 391-400 4 (468)
445-456 5 (456) 381-390 5 (456)
433-444 6 (444) 371-380 6 (444)
420-432 7 (432) 355-370 7 (432)
Power-Up Low Voltage Control Transformer (T5)
The low voltage control transformer, T5, supplies power to the coil of the main contactor K1. It guarantees that
the maximum voltage leaving the Powe

Transformers rarely fail on their own. I fear you have another problem that killed the xformer. I certainly would not install another until you fix the real problem.

steve-l said:

Transformers rarely fail on their own. I fear you have another problem that killed the xformer. I certainly would not install another until you fix the real problem.

Click to expand...

I would normally agree with you, but when I asked has the question... why would this fail... I get back "No idea"... THANKS!

Replaced this with an automation direct transformer, so far no issue bee running for 3 days now. One note, I lost the 208 side, since we have 240V I am not concerned with it too much.

If anyone wants a specific model number from AD, i will provide.

like any electronics, its not a matter of if they will fail, its only when they will fail, as they all do, new or old.

and its a thermal monitor circuit that shows up overheat in the controller. not completely needed.