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Tips/Techniques VFD Terms assistance

Tips/Techniques
Tomc938

Tomc938

Ultra Member
Premium Member
So I've been getting leads ready to go to do a bench test with the VDF before I pull the old motor out and get things lined up with the 3ph motor on my lathe. I would like to use the controls currently on the lathe for the direction of the rotation and the e-stop. I have identified which wires connect to which switches, but the terminology on the VFD has me a bit confused. I have done a bunch of googling, and looking on Youtube, and while there is some good information, I can't seem to find definitions (in English English) for what all the ports do. I'm also wondering about wiring the emergency stop.

Looking at the control ports, FWD and REV are self-explanatory. As is the ground they would have in common. Would you use the "RST" ("External Reset Signal) for the emergency stop, or does this indicate a rest to factory defaults of the unit? Or would you use so helpfully labeled "Lz"(Relay ON/OFF) to control power to the motor?

Thankfully the connections for the pot are clearly explained.

Thanks in advance for the assistance. I'm getting closer by the day!

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Tomc938 said:
Would you use the "RST" ("External Reset Signal) for the emergency stop,
Click to expand...
That would be the RESET, Example. You push your big red button for ESTOP, correct your SNAFU and proceed to turn the lathe back on but it will just sit there flashing or throwing an error, UNTIL you push the reset.
In case of your vevor VFD, it looks like the stop button doubles as the reset.
 
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Hi Tom,

My VFD appears to be a bit different from yours. But I'm pretty darn sure you don't use the internal relay to interrupt motor power. The VFD itself will do that. You might be able to add resistive braking, but it's connections will not be on the control connections bar, it will probably be on the IO connection set.
 
Proxule said:
That would be the RESET, Example. You push your big red button for ESTOP, correct your SNAFU and proceed to turn the lathe back on but it will just sit there flashing or throwing an error, UNTIL you push the reset.
In case of your vevor VFD, it looks like the stop button doubles as the reset.
Click to expand...
Yup. nailed it. There is a setting and I forget which perameter, in that it auto resets if activated
 
Put the e stop switch inline with the common wire for fwd/rev switch if there is no direct e stop connection. It will do the same thing. It will break the common connection if the e stop is pressed.
 
Darren said:
Put the e stop switch inline with the common wire for fwd/rev switch if there is no direct e stop connection. It will do the same thing. It will break the common connection if the e stop is pressed.
Click to expand...
That makes total sense. Was thinking what connections to use, not how to make it happen.:rolleyes:
 
@Tomc938 In the VFDs I have programmed, several of the connections can be programmed to do different things. You might find that there is a parameter you can configure that will define what the RST lead does and its default behaviour.

You might find that the external FWD and REV signals might need to be enabled. On TECO VFDs, you choose to use the front panel switches or the external ones.
 
In industry, if a VFD does not have internal safety functions, it is common practice to run the VFD power through a contactor, and have the common of the control circuit go through an auxiliary contact of said contactor OR a second contact on the ES switch. That’s how I rigged my SM up.

I also had to troubleshoot / commission a new to the machine shop owner client Colchester Triumph VS2500 just the week before last, and that is exactly how that lathe was wired from the factory as well….. the Mitsubishi drive colchester used did not have safety functions built in, so that’s what they did.

That is also the way that other safety critical VFD’s are wired from what I can gather.

Some drives DO have built in safety functions, like the Schneider ATV320 machine drive, or the OMRON line of machine drives…..

I digress.

The Reset input is usually to clear any non-critical faults that come up without having to power cycle the drive. Say you overloaded the drive and the screen was flashing OLF or something similar and you couldn’t run the motor…. Gating the reset input would clear that fault and allow you to run again. Used mostly in more complicated applications…. I would simply just turn the power to the drive off and back on again after it fully drains the capacitors and the screen shuts off… boom, fault cleared.
 
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BaitMaster said:
Some drives DO have built in safety functions, like the Schneider ATV320 machine drive, or the OMRON line of machine drives…..
Click to expand...

I guess it depends on your definition of safety functions. I am totally satisfied with the safety functions built into TECO VFDs and was willing to pay the premium they command to get them. I think the extra cost is also justified because the cost of other external safety circuits that are not required balances out the higher cost.

Beside that, I prefer to KISS.
 
Dabbler said:
@Tomc938 In the VFDs I have programmed, several of the connections can be programmed to do different things. You might find that there is a parameter you can configure that will define what the RST lead does and its default behaviour.

You might find that the external FWD and REV signals might need to be enabled. On TECO VFDs, you choose to use the front panel switches or the external ones.
Click to expand...
I have just briefly looked at the parameter settings, but I believe you are correct on all counts. The explanations of the parameters makes more sense than the terms they used to define the control ports. I guess there's only so much you can do when you try to limit yourself to three letters or less.
 
Gotta love these Chinese directions!

The wiring diagram says connect L and M for single phase 220. On the bottom the power in is labeled R-S-T!

Thanksfully there is a sticker that says connect R and T for 220 1ph.
 
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