Any experience with shunt trip breakers?

PegroProX440 · Jul 25, 2017

I have a newly acquired older Makino SNC64 that will not turn off via control panel. I hit power off and it goes through its 10 second drawback kills power then starts right back up again. A Makino tech thinks it might be a shunt trip breaker not letting it stay off. Is there a way to test this out before dropping 1800 bucks on a new one just to find out that was not the root cause?

ripperj · Jul 25, 2017

I'm not familiar with your particular breaker, but a shunt trip is just a coil that moves an armature that physically trips the breaker open when the shunt trip coil is energized. I can't visualize how a shunt trip could reclose a breaker
It's tough to troubleshoot in this manner with limited info, but it sounds like there is a start signal locked in. I would look at any mechanical switches, typically anything that moves can cause issues

Sent from my iPhone using Tapatalk Pro

Monarchist · Jul 25, 2017

PegroProX440 said:
I have a newly acquired older Makino SNC64 that will not turn off via control panel. I hit power off and it goes through its 10 second drawback kills power then starts right back up again. A Makino tech thinks it might be a shunt trip breaker not letting it stay off. Is there a way to test this out before dropping 1800 bucks on a new one just to find out that was not the root cause?

CAVEAT: Never touched a Makino. This is a "generic" place to look.

Rackmount mailserver, similar symptom.

A cooling fan on the CPU still coasting to a stop generated enough of a back-EMF pulse just as the final shutdown was effected to trigger the restart cycle on the mainboard. Every time.

First "fix" was to manually hold-down the OFF switch for a ten-count after all had gone dark.

Long-term fix was a small resistor in the right place. Cost about five cents.

Worth $1799.95 to look for that? I surely would!

DDoug · Jul 25, 2017

Monarchist said:
Worth $1799.95 to look for that? I surely would!

I hear Mass is nice this time of year.....

ifixcnc · Jul 25, 2017

What breaker is it? No need to pay Makino crazy marked up price, breakers are breakers. Ebay the exact same one for MUCH less. Fuji is common in Makino, some have the shunt trip as an side mount ad on device. I have new in Box 125A and 225A let me know if you need one.

Monarchist · Jul 25, 2017

digger doug said:
I hear Mass is nice this time of year.....

D'ruther do Maine, actually.

But noo I meant for the owner to dig into it himself.

Search

Largest Manufacturing Technology Community on the Web

Search

Any experience with shunt trip breakers?

PegroProX440

Hot Rolled

ripperj

Stainless

Monarchist

Diamond

DDoug

Diamond

ifixcnc

Hot Rolled

Monarchist

Diamond

Similar threads