need motor advice fast: can I use one of these for my grinder?

T

Travis Fry

Joined
Jun 11, 2010
Messages
489
Can I use one of these Baldor motors to run my Bader B2 grinder with a VFD? I know 5 hp is a bit much, but the price is right. Are there any disadvantages?

Here are the specs:


AC Motors | General Purpose |

Specifications: VM3613T

CATALOG NUMBER: VM3613T
FL AMPS: 12.6-11.6/5.8
208V AMPS: --
BEARING-DRIVE-END: 6206
BEARING-OPP-DRIVE-END: 6205
DESIGN CODE: B
DOE-CODE: 010A
FL EFFICIENCY: 87.5
ENCLOSURE: TEFC
FRAME: 184TC
HERTZ: 60
INSULATION-CLASS: F
KVA-CODE: K
SPEED [rpm]: 3450
OUTPUT [hp]: 5
PHASE: 3
POWER-FACTOR: 93
RATING: 40C AMB-CONT
SERIAL-NUMBER: --
SERVICE FACTOR: 1.15
SPEC. NUMBER: 36A003T850H1
VOLTAGE: 208-230/460
 
It's 3 Phase. If you're planning to use it in a home workshop, you
probably don't have 3 phase power, and will have to buy/build a
phase converter.

It'd be simpler, and maybe cheaper,to use a single phase motor.
 
I need a 3 phase to run with a VFD, which is why I'm looking for a motor in the first place. I already have a very good single phase that won't do variable speed.

This may be a nevermind. The frame and shaft sizes are very different, and I'm not sure adapting them would be worthwhile. I came across 4 of these motors for $75 (total, not each) and was hoping to make it work. Anyone have any ideas for using one or more of these in a knife shop that would make this worthwhile anyway?
 
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Travis, will it have its own dedicated line to the breaker box?
Should be ok with a 20 amp breaker. 5hp vfd can be pricey though.
 
It would. I currently only have 110V, so installing at least 1 breaker/plug etc for 220 would be necessary. I've got to get a VFD anyway, and the price difference should be more than offset by the cheaper motors. Can I run smaller (say, 3/4 HP) motors off the larger VFD too?

The biggest issue for me is the face plate size. These motors are bigger, so I'd have to come up with some sort of flange to make it fit. Also, I'd have to drill and tap new holes in my grinder frame AND get either a new drive wheel with a larger shaft capacity, or somehow modify what I have. Like I said, it might be too much trouble, but there's a lot of folks here who know a lot more than me, so I'm hoping some will chime in with some experienced feedback.
 
Baldor recommended super e motors when I talked to them for ac drives. Those can 20:1 turndown, don't know what this motor can be slowed down to.
 
You'd likely want to use a phase converter with a motor that size. Then, add a VFD to regulate the speed.
A new 2hp 3 phase motor with a footed 56C frame is around $179 with free shipping. The larger motors also require non standard drive wheels which can negate cost savings.

You also might not be able to find a 1ph in 3ph out VFD for a 5hp motor...which would then force you to add a phase converter for sure.
 
I think you need to double the amperage for 220V. ie 40amp. You might have 220V/40A off of your dryer or electric stove. On another thread someone indicated a used VFD for a 7.5 HP motor would run @ $1k. Seems like overkill for your needs and costly..
 
Good price, you'd not lose if you got them. That's a nice size for a rotary phase converter motor.

5HP in a single-phase VFD is just about do-able. Not sure how widely available such things are over there, but single-phase 5HP VFDs are not common over here. I'd probably go for one of the Chinese Huan Yang drives off ebay in your position. Don't forget to factor in the cost of an enclosure and local control if you do.

If you want to go that way, you can effectively set yourself up with a 3-phase variable-speed shop. Using plugs for each motor and a trailing control box for the VFD, it's quick to change between machines.

VFDs will run smaller motors fine. I actually tend to leave mine set on the maximum current setting, if I'm using it for plugging in different motors. Where I have a VFD hard-wired to a motor, I use the rating-plate data off the motor and get the benefit of the protection system built into the VFD.
 
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