VFD -leave in standby or wire in a switch

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martik777

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When I press stop, my VFD remains in standby (Can't find any settings to change this). How much current does a VFD typically draw in standby? I guess I could wire in a switch but seems like a pain to have to press stop AND flip a switch when you are done for the day.
 
I added a wall switch to turn off the VFD. I do not find it a pain to turn it on at the beginning of a day's use and then turn it off at the end of the session. If the machine was being used every day, I would probably just leave it on.
 
martik777 said:
When I press stop, my VFD remains in standby (Can't find any settings to change this). How much current does a VFD typically draw in standby? I guess I could wire in a switch but seems like a pain to have to press stop AND flip a switch when you are done for the day.
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Very little. I have 3 that are on continuously. My power usage in my shop as I write this is 554 watts. That includes 4 VFDs, 3 computers, 3 CNC control systems, lathe DRO, various battery chargers, and a refrigerator (which just happens to be running at the moment). The VFDs are a very small fraction of that.

On the other hand, just shutting down my CNC lathe requires more than just flipping one switch:
In this case the spindle VFD is shut down at the end of the day.
Press E-stop, shuts down servo drives and puts VFD into E-stop mode
Press Control Power Off, shuts down hydraulic pump and a couple cooling fans, removes power from a couple other systems
Flip the Main Cabinet Disconnect to Off, removes main power to the lathe, turns off a couple more fans, but leaves the computer and control system up
Press E-stop on the RPC, shuts down the RPC, leaves the RPC startup VFD, and control system hot.

So flipping an extra switch at the end of the day isn't terrible. :)
 
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I switch them off. Most times drives are designed such that leaving the power on leaves the input bus capacitors powered up and that leaves the high voltage DC applied to them and to the power transistors (340VDC at 240VAC input). That does take very little energy. There is also some small power draw by the electronics. The bus capacitors are likely the single least reliable component in the drives if other components are designed in with similar margins. I assume that the hobby grade drives have to be designed close to the edge so they can be low cost and therefore use components closer to their ratings than an industrial drive might. So, it is likely that turning off the power for 50% of the time or more would increase the input bus capacitor lifetime since the capacitors are not charged to close to their max ratings for as long. Also, taking them offline would somewhat isolate them from power surges at night, like those induced onto the power lines by nearby lightning storms. When they do fail, usually these capacitors fail in a reasonably well behaved way but not always. This is why I switch mine off at night. BTW I also unplug the coffee maker, toaster, turn off all satellite boxes, computers etc. when we're on vacation. I have only a little trust in the quality and the safety, of these "throw away" things. So I probably am a little biased on this subject.
 
I pull my VFD's plug from the wall outlet. :dunno: Works for me. I don't want to leave it on, even in standby.
 
The ones I work with everyday, on the boilers, pumps and fans are on 24/7/365, some setting in standby mode for weeks at a time, so I see no difference at home, I just leave them on. I switched over to 100% led lights in the shop, I haven’t turned them off in about 5 years.
 
I have a switches on mine. I may go weeks without using a specific machine. It's not much but why waste the energy. I also unplug unused wall warts. Every penny I save can buy tools! :)
 
Is it better for the capacitors to stay powered up, or turned on and off daily? Or another way to phrase the question, is the life of the capacitors more affected by cycling on and off, or by the time it is on?

I read many years ago, that it is the cycling on and off that is the bigger factor, so most of mine have been on for over five years now.
 
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