VFD KBAC - 27D and 2hp 17xx rpm Motor - Help Please

H

Heli00

Joined
Oct 19, 2017
Messages
340
Hi,

I decided to go with a VFD for my KMG grinder and direct drive over the 3 poolies stock system I’m using right now.

Here is what I decided to go with:

VFD: KBAC - 27D 2.0 HP, 6.7A, 230 VAC 3ø Output,
MOTOR: 2 hp, 230V, 17xx rpm, 3phase, TEFC, 56C frame. Didn’t yet decided on brand.

So here are my dilemmas.

1. There are a bunch of options listed for the VFD. From KB website:
Options:
a. On/Off AC Line Switch,
b. Forward-Stop-Reverse Switch,
c. Run-Stop-Jog Switch,
d. Signal Isolator with Auto/Manual Switch,
e. Class “A” (CE) RFI Filter and
d. Liquidtight Fittings.

Do I need any of this accessories and if yes which and why please ? What are the
minimum options to have in your oppinion?

2. What brand motor should I go with? Is something like Leeson, Baldor ? Could you give me a brand and model that works well with your setup?
Since I will double the speed of the motor through some jumpers in the VFD, I wonder if less expensive motors would be able to cope with this.
Are there any other specific requirements on the motor that I need to be aware of when choosing one?

3. Motor shaft diameter 5/8”, keyed. Is this what I need?

4. Where to buy? Good deals.

Thanks again,
Constantin
 
IIRC, a stock KB drive only comes with the Forward/Stop switch. I added a power on/off switch and the FOR/STOP/REV, though you don't necessarily "NEED" these. If you plan on running a seperate disc grinder, or reversing your grinder for sharpening, I'd get the FOR/REV switch added. As for the power switch, another option is simply wiring a switch to your power feed (DPST for 220VAC), or turning it off at the breaker panel. It won't necessarily hurt it to leave it powered 24/7, but I don't like to do that personally.

You probably won't need d. or e.; Those are typically used in more industrial applications where there's a lot of different motors and machines running on the same feeds, or where electrical noise/interference might be an issue. The auto/manual switch is for more specialized applications as well.

The liquid tight fittings aren't a bad idea. You want to at least be "dust proof" where your power and motor cables go into the chassis.

I recommend SO cable/cords for the power cord and the cord to the motor. The motor will require 4 conductors, and the power cord needs 3. You can use the same for both, you'd just cut the 4th wire out when you wire the plug. Your cable glands (waterproof connectors) will be sized accordingly. I think I used 12 gauge for mine, though I believe 14 gauge is suitable as well (I don't recall the amp draws for a 2 hp KBAC drive at the moment, but 14 gauge is good for up to 15 amps, and 12 gauge for 20 amps)

Motor brand: IronHorse motors from Automation Direct is about the best "new" value for the money. Leeson and Baldor are great too, though a little pricier. You'll want a 56C frame size. That will allow a direct face mount, and the shaft will be 5/8" diameter. It's recommended that you get Inverter Duty, which basically just means that the insulation is heavy enough to withstand running off of a VFD. A motor with "Class F" winding insulation is the same thing. A non "inverter duty" motor would still work, but it just may fail faster (which for us hobby makers could still translate into years of use).

That's really about it. As for where to buy, it used to be that ElectricMotorWholesale.com had the best prices for KB drives, and AutomationDirect.com had good motor prices, but with eBay and Amazon sellers popping up left and right, it may be that you could find what you need for a few dollars cheaper via those sites. It's possible that you'll have to wire your own switches if you go that route, but they're simple to install.
 
Heli00 said:
Hi,

I decided to go with a VFD for my KMG grinder and direct drive over the 3 poolies stock system I’m using right now.

Here is what I decided to go with:

VFD: KBAC - 27D 2.0 HP, 6.7A, 230 VAC 3ø Output,
MOTOR: 2 hp, 230V, 17xx rpm, 3phase, TEFC, 56C frame. Didn’t yet decided on brand.

So here are my dilemmas.

1. There are a bunch of options listed for the VFD. From KB website:
Options:
a. On/Off AC Line Switch,
b. Forward-Stop-Reverse Switch,
c. Run-Stop-Jog Switch,
d. Signal Isolator with Auto/Manual Switch,
e. Class “A” (CE) RFI Filter and
d. Liquidtight Fittings.

Do I need any of this accessories and if yes which and why please ? What are the
minimum options to have in your oppinion?

2. What brand motor should I go with? Is something like Leeson, Baldor ? Could you give me a brand and model that works well with your setup?
Since I will double the speed of the motor through some jumpers in the VFD, I wonder if less expensive motors would be able to cope with this.
Are there any other specific requirements on the motor that I need to be aware of when choosing one?

3. Motor shaft diameter 5/8”, keyed. Is this what I need?

4. Where to buy? Good deals.

Thanks again,
Constantin
Click to expand...

Good choice, that's really the way to go.
Get all the switches.

a. On/Off AC Line Switch, - either that, or unplug it when you're done
b. Forward-Stop-Reverse Switch, - you can use that vfd later on a disc, or sharpen backwards or something


c. Run-Stop-Jog Switch,
That one is included



d. Liquidtight Fittings.
You can get them locally at a home depot, but order direct if you want - it's simpler


2. What brand motor should I go with? Is something like Leeson, Baldor ? Could you give me a brand and model that works well with your setup?
Since I will double the speed of the motor through some jumpers in the VFD, I wonder if less expensive motors would be able to cope with this.
Are there any other specific requirements on the motor that I need to be aware of when choosing one?

You will pay an arm and a leg for a baldor, leesons are good, but the no name chinese motor from autoahion direct works fine too.

3. Motor shaft diameter 5/8”, keyed. Is this what I need?
Yes 56C frames are all like that.
 
Just wanted to mention what great guys, @Matthew Gregory and his friend Joe are for hooking me up, and many more knifemakers, with a KMG direct drive kit.
Matt, please extend my thanks and gratitude to Joe.

I really don’t have words to express my gratitude to both of them!!! And Matt is not even making a dime on this, what a guy!!! I will take Matt and Joe out for a nice dinner and some beers this summer, you can count on it.

What a great community, makes you humble!

Thank You,
Constantin
 
You must log in or register to reply here.
Back
Top