Wiring VFD with no backup supply

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ashesman
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Wiring VFD with no backup supply

Post by ashesman »

I am switching from a Hitachi SJ-P1 to a Delta C2000. The SJ-P1 has a separate power input for the logic and inverter. When E stop is pressed, the main contactor disconnects main power to the inverter, but it's logic remains powered and it keeps trucking on. Eventually it faults due to loss of power supply...

The C2000 has only one power supply input. The manual says it should be wired through a safety contactor and I intended to wire it to the same powr supply I am currently using. This means that on E-Stop, the VFD will be powered down completely. A bit nasty given the inrush current that occurs every time it is turned back on.

I know C2000s are commonly used, so I am wondering how people wire them. I was wondering about powering the drive without a contactor and putting E-Stop through the STO terminals. Thoughts?
cncsnw
Posts: 2321
Joined: Wed Mar 24, 2010 5:48 pm

Re: Wiring VFD with no backup supply

Post by cncsnw »

I think keeping line power on, and using E-stop to interrupt the STO circuit, is a good way to go.

You may still need some refinement to your PLC program.

If the C2000 is like the Automation Direct GS4 (which is also a current-generation Delta drive with an STO feature), then it will report a Fault condition when the STO circuit is open. Your PLC program, then, must only consider the spindle drive to be faulted if the fault relay activates while the Emergency Stop circuit is closed.

E.g.

Code: Select all

IF !SV_STOP THEN NoFault_T = 1000, SET NoFault_T
IF SV_STOP THEN RST NoFault_T
IF NoFault_T && !SpindleInverterOk
  THEN FaultMsg_W = SPINDLE_FAULT_MSG, SET SpindleFault_M
ashesman
Posts: 272
Joined: Thu Dec 03, 2020 4:54 am
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Re: Wiring VFD with no backup supply

Post by ashesman »

Thanks. Secretly I was hoping someone would say using STO was a bad idea and just cut the power! That's how the SJ-P1 is wired. It is a really big job to change the power wiring due to how crammed it all is. And hard to make it nice again.

Guess I will get it running first to see if it actually works to do orient. The last three drives haven't worked!

My PLC program will need a big change as currently it manages orient in a PID loop.

God I hope this drIve works properly!!!
ashesman
Posts: 272
Joined: Thu Dec 03, 2020 4:54 am
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DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: Wiring VFD with no backup supply

Post by ashesman »

Just to follow up on this, STO cant be used as requires a power cycle to reset any STO fault. So, may as well just run the drive off a relay...

There is an emergency stop digital input option that can be used. It may not be quite as safe as a proper hard power cut or STO but will do the job to let you keep the VFD powered during ESTOP.
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