Size wire and Fuses for a VVVF drive

[TheElevatorGuy]

It is my understanding from the code that wire size is based on 125% of the input Amps of the drive. Can someone tell me how to size the fuses feeding it? Thanks in advance.

 

[tom baker]

Check the mfg instructions, they often will specify a specific fuse type, such as. Type T, and size
What is a VVVF?

 

[kwired]

If you carefully read instructions often the expensive current limiting fuses are often only required when available fault current is over a certain level.

Reality is if front end of drive develops a fault, all the current limiting fuse will do is possibly lessen how spectacular of a show the fault event will be. The drive is still damaged.

 

[tom baker]

It’s difficult to protect IGBTs in a drive, they are much faster than a fuse if the drive output faults

 

[noonan]

variable voltage variable frequency?

 

[TheElevatorGuy]

variable voltage variable frequency?

Yes. That is the name I have always known them to be. Is there a different name you know? Thank you.

 

[TheElevatorGuy]

Check the mfg instructions, they often will specify a specific fuse type, such as. Type T, and size
What is a VVVF?

Variable Voltage Variable Frequency. I checked with the manufacturer and they specify the fuses required. Thank you for your help.

 

[zbang]

Much more usually "Variable Frequency Drive" or VFD (I've never heard vvvf, either). Some people even shorten VFD to "the drive", which I find a touch ambiguous.

"Many fuses are protected by fast-blowing electronic components"

 

[TheElevatorGuy]

Thank you Z. I agree with you. "The drive" for the elevator industry could refer to and SCR drive or a VFD. There are many more D.C. motors in New York City running elevators than A.C. motors however anything installed new is requested to be A.C.