Got a 3 phase electrical question

henery97

Member
Apr 4, 2011
206
0
16
Nebraska
You can run a 3 phase input vfd on single phase, you just need to derate the drive. Allen Bradley says to derate by 65%, idk what Siemens or another mfg would derate by. But it's another option if you could come across a cheap used drive.
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
You can run a 3 phase input vfd on single phase, you just need to derate the drive. Allen Bradley says to derate by 65%, idk what Siemens or another mfg would derate by. But it's another option if you could come across a cheap used drive.

single phase input / 3 phase output VFD's can only handle up to ~3hp.
 

bobxr50

Been around
Mar 3, 2008
61
2
8
mn
single phase input / 3 phase output VFD's can only handle up to ~3hp.


There is a other manufactures that can do 5 hp. Single to three phase. Most only do 3 hp.

The 5 hp ones that I have installed didn't last two years. So I do not install them anymore.

You can run a 3 phase input vfd on single phase, you just need to derate the drive. Allen Bradley says to derate by 65%, idk what Siemens or another mfg would derate by. But it's another option if you could come across a cheap used drive.


Yes you correct. To play it safe with all manufactures I calculate using 50% derate to size single to three phase.
 

henery97

Member
Apr 4, 2011
206
0
16
Nebraska
single phase input / 3 phase output VFD's can only handle up to ~3hp.

You can use a big (15hp in this case) vfd that is supposed to have 3 phase input and run it on single phase. You just have to derate the drive per the mfg. I'm not talking about a small drive that is supposed to be single phase input.
 

duratothemax

<--- slippery roads
Aug 28, 2006
7,139
10
0
Wyoming
You can use a big (15hp in this case) vfd that is supposed to have 3 phase input and run it on single phase. You just have to derate the drive per the mfg. I'm not talking about a small drive that is supposed to be single phase input.

ahh interesting! I did not know that, thanks for the info.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,743
5,911
113
Phoenix Az
Just to update this, wound up bidding and winning a new Baldor single phase motor for 300 shipped. The 56h frames worried me with the small 5/8" shaft and the fact Id have to run a small pulley so belt/pulley contact would be small.

Now to get it home and install!!
2b90f693ace1860e5c138121a312f713.jpg
 

Awenta

Active member
Sep 28, 2014
4,090
2
38
CT
Seems like the right way to go. Good deal too! Have fun!

Sent from my SM-N910V using Tapatalk