vfd switching for test
vfd switching for test
(OP)
I am about to hook up a VFD to a 3HP motor and familiarize myself with the menus and whatnot on it. As a general practice, when I'm using 230v I usually throw some type of switch in between what I'm playing with and the incoming power to save me a trip across the shop to the switch on the wall. (which may be questionable by itself here)
I understand that VFD's are susceptible to noise caused by bounce and other occurrences introduced by mechanical switches...my question is HOW susceptible? I plan to use an overload with a START and a STOP button on it...seems to have a sort of sliding action when making, and a pretty rough sounding breaking action.
Would a 3 phase on/off switch be better? (similar to a lightswitch)
Any thoughts appreciated...
I understand that VFD's are susceptible to noise caused by bounce and other occurrences introduced by mechanical switches...my question is HOW susceptible? I plan to use an overload with a START and a STOP button on it...seems to have a sort of sliding action when making, and a pretty rough sounding breaking action.
Would a 3 phase on/off switch be better? (similar to a lightswitch)
Any thoughts appreciated...





RE: vfd switching for test
Powering up a drive is probably the most stressful event in a drive's life. They run best and longest if powered up and left that way using the control terminals for all control features.
Also, the drive software will have the capability of doing thermal overload protection for the motor. You do not need an external overload device except for unusual applications like multiple motors on the same VFD.
RE: vfd switching for test
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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RE: vfd switching for test
I have seen 'overcautious' guys doing incredible damage to simple gear. It is good that you asked here. That will help you a lot.
BTW, switching a VFD on is usually not very critical, don't let that frighten you. But lots of switching on/off shall definitely be avoided. And, please, do not open the output while running. That is bad practice and very seldom needed.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: vfd switching for test
Incidentally, will applying power to the VFD without a motor do any harm....just to go through the parameters....I figure as long as it's not trying to turn the motor it would be ok...?
RE: vfd switching for test
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: vfd switching for test
if it is just for parameter familiarization, why not check if the VFD has the ability to power the control section (including keypad)from an external 24vdc power supply. I know our drive can do this (with an option card) and I know of a couple others that can also. It means you are not having to connect 230+ voltages to the power section that, as already explained, have the potential to damage the VFD if not applied correctly.
You would not be able to run the output of the drive or connect/run a motor but it sounds like you don't really want to do this anyway.
RE: vfd switching for test
RE: vfd switching for test
Now we have blown up a drive once while moving a connected filter and a bare braded ground strap touched an output terminal...oops. Bad practice moving live parts.
Neil
RE: vfd switching for test