3 phase line in swapping with a VFD

I was relocating some press rollers recently. Cabinet was 3 phase and contained a VFD.

Basic controlls:

Button 1 raise the rollers
Button 2 lowers the rollers
Joystick up forward motion
Joystick down reverses motion.

When we applied power (BOY), the buttons were reversed, yet the joystick were working as labeled.

We swapped two legs and that fixed the issue. Buttons acted as they should have. And the joystick still operated as before, correctly.

I imagine swapping legs does not effect the VFD and assume that the buttons were independent of the VFD and on a transformer.

Any insight would be appreciated

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bwat

EE
Location
Western PA
Occupation
EE
Just a guess, but the rollers up/down was with a regular contactor type control (across the line...no VFD) so phase sequence matters. The joystick control for forward/backward is controlling the VFD which does not care about phase sequencing at the input to the VFD. So swapping phases matters to the up/down, but not for the forward/reverse.
 

paulengr

Senior Member
With rare exceptions (cycloconverters) which you are very unlikely to see a VFD converts to DC then back to AC so the input phasing doesn’t matter at all.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Yeah, the VFD always puts out clockwise rotation regardless of input. This makes finding correct rotation when hooking up temporary generators much more difficult. We used to check the indoor fan rotation on RTU’s to verify correct rotation, but many manufactures and retrofit applications are using VFD’s to control the fan. The compressor itself is still straight contactor control, so it could be running backwards even though the fan is running correctly.
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Input power rotation to the VFD is totally irrelevant, all the VFD does is convert it to DC.

Output power can be chnaged on programming, no need to swap conductors. There will be a parameter that you can use to tell the VFD what rotation to give to the motor.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Input power rotation to the VFD is totally irrelevant, all the VFD does is convert it to DC.

Output power can be chnaged on programming, no need to swap conductors. There will be a parameter that you can use to tell the VFD what rotation to give to the motor.
Now that you said that, I do remember years back when we were installing vfd’s on exhaust fans for a refrigeration rack room, I was able to change the rotation in the setup menu, and didn’t have to swap wires. We don’t do a whole lot of vfd work. Big Ass Fans is the last vfd’s I had to work with.
 

kwired

Electron manager
Location
NE Nebraska
Now that you said that, I do remember years back when we were installing vfd’s on exhaust fans for a refrigeration rack room, I was able to change the rotation in the setup menu, and didn’t have to swap wires. We don’t do a whole lot of vfd work. Big Ass Fans is the last vfd’s I had to work with.
Or with many you can just move your single direction input lead to the reverse terminal instead of the forward terminal.
 

kwired

Electron manager
Location
NE Nebraska
Or with many you can just move your single direction input lead to the reverse terminal instead of the forward terminal.
If running directly from keypad you might be set up that you can use a forward or reverse labeled button on the keypad.
 

PhenixFord

Member
Location
Cabot, AR.
Occupation
Industrial Systems and Controls
If running directly from keypad you might be set up that you can use a forward or reverse labeled button on the keypad.
Most of them are selectable just by changing a parameter.
Local - Key Pad
Remote - Field Wiring (IE: Discrete Digital Input)
Comm - Err -Communications Network
 

kwired

Electron manager
Location
NE Nebraska
Most of them are selectable just by changing a parameter.
Local - Key Pad
Remote - Field Wiring (IE: Discrete Digital Input)
Comm - Err -Communications Network
Correct. some don't even have definite function for some or even all the inputs and function can be selected via parameters.
 

PhenixFord

Member
Location
Cabot, AR.
Occupation
Industrial Systems and Controls
Correct. some don't even have definite function for some or even all the inputs and function can be selected via parameters.
I've worked with Siemens Master Drives and Vector Control Drives that actually take that concept one step further by enabling the user to select exactly how they want to use the I/O. Any terminal can be Input, Output, Voltage or Current. - Those are a PITA to program.
 

kwired

Electron manager
Location
NE Nebraska
I've worked with Siemens Master Drives and Vector Control Drives that actually take that concept one step further by enabling the user to select exactly how they want to use the I/O. Any terminal can be Input, Output, Voltage or Current. - Those are a PITA to program.
I never used a Siemens drive.

Also seem to find most Siemens products to be a PITA.
 

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Electrician - 2017 NEC
one step further by enabling the user to select exactly how they want to use the I/O. Any terminal can be Input, Output, Voltage or Current. - Those are a PITA to program.
I though about getting one of these personally just to tinker with since I like Arduino. Anybody ever use these? My first impression was that they were mickey-mouse toyish but, after reading I don't think that's the case. Just non proprietary, which could be good or bad.

https://www.automationdirect.com/videos/video?videoToPlay=kPIZK1tTxvo
 
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