What's new
What's new

Total noob here, how do I use a VFD to run my 1HP, 3ph motor on 2ph or possibly 1ph power?

easternMaine

Plastic
Joined
Nov 23, 2022
I recently bought an old Delta Milwaukee wood shaper that uses a 3 phase motor.
The Motor is 1hp 2850rpm/3450rpm, duel volt 208-220v/440v,
What VFD should I buy?
 
You probably have 230vac single phase for input power.

A 2 to 5 Hp VFD. At least 1.5 times your motor hp of 1. The general rule for single phase input.
You can buy a three phase input VFD and connect your two single phase lines to two of the three inputs. Like everybody else.
I would keep the rpm to 2850.

If you looked around for a few 2 - 5 hp VFDs and asked for opinions you might get more help.
If you have plans for more hp in the future you can always buy up to something like 5 hp.
Start with this link for 2 hp drives.

(no endorsement for wolf)
 
Last edited:
Most VFDs in this power range will run off of single phase.
You are only using part of the input rectifier so that is why you need to oversize the HP rating.
Once you get up into 5hp some (many) will bitch if they do not have all 3 phases incoming.
 
Not sure why one would want to buy a VFD off of Amazon, go to a legit dealer distributor.
 
Does anyone here actual evidence that a HuanYang VFD is that bad for the price? Sometimes chinese junk is good enough. I think i'm going with them.
 
Oh, any mention of them here was banned a bit back. Many threads.
Not super great but I have a few that have not died and been good to me.
Will they do 40+ years, I do not know yet.
Bob
I read somewhere about fan noise on them being load. Are yours that bad?
 
Not sure why one would want to buy a VFD off of Amazon, go to a legit dealer distributor.

With a brand name model would i still need to got one that's 1.5 times my motor hp? Also would it be possible to have more than one device hooked to to if I only ran one at a time?
 
With a brand name model would i still need to got one that's 1.5 times my motor hp? Also would it be possible to have more than one device hooked to to if I only ran one at a time?
Depends..
In the US -- seemingly -- the convention is that you need 1.5x the nameplate HP.

In the EU, we get nameplate power in by kW and nameplate power out by kW and no-one derates anything.
But all our power is 220V (or 3 phase 220 or 380V) and no 110V stuff exists.

A device meant to run heavy loads off 220V will have much higher heating at 110V. About 4x more.
So it will work fine off 110V but will quickly fail if run at full capacity for extended times.
Electronic stuff fails mainly due to heat.
10s k experience.

My hitachi 2.2 kW VFD explicitly supports 3 different configs, for different use.
I would not do such, today, because cheap vfds abound.

A switch for 4+1 wires to connect to the load (220V 2 kW) costs more than the vfd.
Endless ways to bodge the connection, not according to code, and I would neither advise them or install them.

In Finland electrical installers are somewhat responsible.
In germany, wholly responsible.
In Spain, theoretically responsible.

Spanish installs are generally a major snafu and carry little in common with the electrical drawings.
Lots of experience.
 
Depends..
In the US -- seemingly -- the convention is that you need 1.5x the nameplate HP.

In the EU, we get nameplate power in by kW and nameplate power out by kW and no-one derates anything.
But all our power is 220V (or 3 phase 220 or 380V) and no 110V stuff exists.

A device meant to run heavy loads off 220V will have much higher heating at 110V. About 4x more.
So it will work fine off 110V but will quickly fail if run at full capacity for extended times.
Electronic stuff fails mainly due to heat.
10s k experience.

My hitachi 2.2 kW VFD explicitly supports 3 different configs, for different use.
I would not do such, today, because cheap vfds abound.

A switch for 4+1 wires to connect to the load (220V 2 kW) costs more than the vfd.
Endless ways to bodge the connection, not according to code, and I would neither advise them or install them.

In Finland electrical installers are somewhat responsible.
In germany, wholly responsible.
In Spain, theoretically responsible.

Spanish installs are generally a major snafu and carry little in common with the electrical drawings.
Lots of experience.
I am in the U.S so would probobly need the 1.5x power. Another question is should go with 220v input power or 120v for my 1hp 2850rpm/3450rpm motor?
 
Get a VFD designed for 3-phase input, 220 volts.
Feed it with single phase 220 volts, but you'll need at least 1.5 times power of your motor, because you're feeding it with single phase.
Make sure there are no swithes between you VFD out and the motor. Put a small toggle switch, or similar for the VFD control.
You can feed more than one machine off a single VFD; one simple way is to wire VFD output to a receptacle, and then plug in whichever machine you want to use. Make sure its rated for highest power motor.
I've installed about 8, and counting Fuji VFDs. They are fully industrial reliable VFDs, and not really that expensive, with great technical support.
This one would probably be ideal:

I've had great success and support from Marshall-Wolfe, and Fuji.
Bob
 
You do not need to upsize the VFD, as long as the output amps of the VFD are sufficient (more than) the motor amperage. You can either use a voltage doubler type of VFD that has a 120V input and outputs 230VAC 3 phase, or you can go with a single phase input 230VAC VFD if you have 230VAC available. I prefer the latter, but either one will work equally well for this Hp rating, beyond 1 Hp you should stay with 230VAC input voltage. The Teco model recommended was because they work well at that price level, I have seen them running for decades, and appear to have goo reliability. The L510 should be easy to install, there are also others like the KB electronics KBDF-24D which can be run off of 115 or 230VAC and is similarly priced. The manual's are readable, the parameters are not overwhelming to understand as opposed to some of the higher end VFD's, you get technical support. HY VFD's and similar bargain basement VFD's are banned in this forum, and for good reason.

Please note that older motors the insulation may be more marginal and may be more susceptible to long term damage if the VFD parameters are pushed (like high carrier frequency/overload).
 








 
Back
Top