converting VFD from 120v to 220 v

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Cushing H.

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I suspect I know the answer to this, but 1) I am being lazy and , 2) I just thought it was worth the discussion/ engagement with my brethren on the forum....

Bittersweet times ... I am in the final process of packing up my shop to move to KY, and just hit packing up my grinder. good news/bad news .... my current shop only realistically had 120 v to power the grinder (so that is what I ordered from ameribrade). The good news is that my new location has plenty of electrical capacity, and definitely clear wiring capability to run 220 volt to the grinder. So ... the VFD I have ( listed as being from KB electronics, FL) is listed as being capable of having input from 120v to 220V. so, I guess my question is .... is it typically a really straightforward process to convert these VFD devices from 120v to 220v input (or vice versa)??
 
Yep, it will be for 220vac 1ph input with 3 ph output for your 3ph motor. Your output wiring shouldn't need changing at all. Looks like the input will still be connected to L1 & L2 terminals with jumper J1 moved from "115V" to the "230V" position as Stacy said. From page 13 of the KBAC series manual:
"Models KBAC-24D, 27D: Designed to
accept single-phase (Terminals “L1”, “L2”) AC line input only. Rated for 208/230 Volt AC line input with
Jumper J1 set to the “230V” position (factory setting). Rated for 115 Volt AC line input with Jumper J1
set to the “115V” position. See Figure 7."
 
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Ken H> said:
Yep, it will be for 220vac 1ph input with 3 ph output for your 3ph motor. Your output wiring shouldn't need changing at all. Looks like the input will still be connected to L1 & L2 terminals with jumper J1 moved from "115V" to the "230V" position as Stacy said. From page 13 of the KBAC series manual:
"Models KBAC-24D, 27D: Designed to
accept single-phase (Terminals “L1”, “L2”) AC line input only. Rated for 208/230 Volt AC line input with
Jumper J1 set to the “230V” position (factory setting). Rated for 115 Volt AC line input with Jumper J1
set to the “115V” position. See Figure 7."
Click to expand...
Sounds good. I will obviously need to change the plug though.

I wonder just how much difference I will find? I dont do a lot of really heavy grinding .... often at lower speed and lighter pressure. But every once in a while I *do* lean in to it.....
 
You'll need to look at the 220 vac recept to see what plug is required. There are several different sizes, all depending on the amperage the recept is wired for. Doesn't matter if it's a 50 amp dryer/stove (crowsfoot) plug or a smaller 20 amp, just just need to check the recept before purchasing a plug.

The motor will never know the difference between 120 and 220 vac. The magic takes place inside the VFD and the motor sees exactly the same voltage/freq regardless of which voltage is the input. That's "assuming" the 120 vac input has sufficient amperage (and wire size) to handle the load without excessive voltage drop.

Now that I wrote all that, what size motor do you have? If a 2 hp was was derated for the 120vac input, then you'll have a full 2hp with your 220 vac input and might tell a bit of difference when really leaning to hog some metal. 2hp with a 36 grit belt will really throw some sparks :)
 
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The receptacle has a number on it. For instance, it may be a NEMA 6-20R. You want a NEMA 6-20P plug.
 
Ken H> said:
You'll need to look at the 220 vac recept to see what plug is required. There are several different sizes, all depending on the amperage the recept is wired for. Doesn't matter if it's a 50 amp dryer/stove (crowsfoot) plug or a smaller 20 amp, just just need to check the recept before purchasing a plug.

The motor will never know the difference between 120 and 220 vac. The magic takes place inside the VFD and the motor sees exactly the same voltage/freq regardless of which voltage is the input. That's "assuming" the 120 vac input has sufficient amperage (and wire size) to handle the load without excessive voltage drop.

Now that I wrote all that, what size motor do you have? If a 2 hp was was derated for the 120vac input, then you'll have a full 2hp with your 220 vac input and might tell a bit of difference when really leaning to hog some metal. 2hp with a 36 grit belt will really throw some sparks :)
Click to expand...
The bad news is that there IS no receptacle (currently) . The good news I get to install whatever I want, wherever I want! :) .

I thought I had always heard that if you run a VFD on 120v that the motor is automatically derated .... and so if I feed 220 to the box I should get the full capacity of the motor..... ???
 
Cushing H. said:
The bad news is that there IS no receptacle (currently) . The good news I get to install whatever I want, wherever I want! :) .

I thought I had always heard that if you run a VFD on 120v that the motor is automatically derated .... and so if I feed 220 to the box I should get the full capacity of the motor..... ???
Click to expand...
That's only the case for a 2+ HP motor, which gets throttled to 1.5 HP on a KBAC-27D on 120V. If you have a 1 HP motor, it does not make a difference.
 
Hubert S. said:
That's only the case for a 2+ HP motor, which gets throttled to 1.5 HP on a KBAC-27D on 120V. If you have a 1 HP motor, it does not make a difference..
Click to expand...
Looks like the motor I have is 2HP .... so I should get a bit of a bump. The unfinished area in the new house is totally unwired (except what is necessary to power the furnace, communications point-of-presence, and the sump and ejector pump, so I need to run wiring anyway .... for the grinder it will be just as easy to run 220v as opposed to 120v, so no reason not to ......

I am SO ready for this move to be done with. among the other stressors ..... no shop, no fun (and also duller knives, as my grinder which I use to sharpen is down.....). definitely looking forward to having more space to work in though (who knows, I might finally be able to get that disk sander. Also, the backyard has no neighbors, so I can work with a "firing range" in terms of a potential buffer......
 
You've got a 2hp? Great news on that. As Stacy said go with the NEMA 6-20R setup - and use the dual recept since you're wiring them in. That way you can have the disk grinder and 2X72 both plugged in at same time.
Do a search on Amazon #B0BRTPL7TZ and a link will pop up to a pair of them - might as well wire in more than 1 recept while you're at it:)

Shooting range? I'm jealous - I had one here until they built a new subdivision right up to my "back Forty" fence.
 
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