Bandsaw replacement motor help..

[Michael Menzli]

Greetings Creekers,

I purchased a new 3 hp motor for my Harbor Freight bandsaw yesterday. I wanted to go with the 2hp however the shaft is a 1/4" larger for some reason I realize this is beyond overkill and will likely strain the system. I wanted to give it a shot for curiosity sake.

Anyways in my excitement I overlooked a really important fact.. this motor is set at 240v only. Ive researched a bit and will be using a 30 amp double pole breaker and 10 gauge wire.

Now the confusion.

Per the instructions it lists wires as p1 t1 l1 etc. Is L1 considered black and the L2 white from my main circuit or vice versa? I want to run this ccw.

Secondly. I would like to continue to use a switch to power on and off. Can I use the original switch mounted on the saw. Can I basically cut the plug and wire in one designed for the 240 circuit or will this become overloaded? If I cant use it what would be recommended. I only have big box stores to gather materials.

Thanks in advance
Michael

[Salem Ganzhorn]

Michael, I am not an electrician and if you electrocute yourself it is not on me .

But most 3hp motors are fine on a 20a circuit. Check the motor label for amperage.

Most inexpensive tool switches are 110v only but check the label on the switch it will tell you. Grizzly sells good switches for cheap.

As for motor direction it has nothing to do with how you wire it to the wall (for single phase). The two hot leads on a 220v circuit are interchangable. Check the motor label for direction. Some motors only turn one way. Others are reversible and the label will tell you how to wire it. Switching direction is done by reconfiguring how the internal leads are connected.
Good luck!
Salem

[Michael Menzli]

Thanks Salem..thats exactly what i needed. I dont get why things cant be explained in simple terms. Ive got it wired up for ccw per the instructions

Now...as far as switches. I purchased a 30 amp double pole single throw light switch rated for 277volts. Im confused as to how this works on a 240 volt circuit. Ive wired the 240 as 2 hots and 1 ground with no neutral. Can this switch be used to power the saw on and off? I have installed a 20 amp circuit breaker box as well but want that for safety and not to turn my machine on and off

[Jack Wilson]

Michael, the amperage is what you need to consider, not the voltage. 3 hp @ 220-240V ought to run around 15 amps or so, that can be carried on 12-2 with ground, and a 20 amp double pole breaker. The black AND the white wires will BOTH be hot, one on each terminal of the breaker, ground goes to grounding bar. The switch? Sounds like its rated for 3 phase @ 277. I am not too sure about that.

[Salem Ganzhorn]

I think both amperage and voltage is important for the switch. You should not exceed either of the specifications. And I agree with Jack that 277 screams 3 phase. Could you use this to disconnect a 1 phase circuit? Probably but I have no idea how . You can buy a 220v 20a switch pretty cheap from HD/Lowes. I am not sure if this is kosher or not but I use the breaker as the disconnect. I have 4 small children and I shut it all down from the panel when I close up shop.

As for wiring you probably want a 220v 20a breaker, 12 gauge wire and an approved 220v 20A receptacle. You probably should also get it inspected. It will cost 40-50$ but you will know it is up to code. The inspectors in my area are quite nice and take the time to help a home owner (note they are NOT nice to electricians ).

Good luck!
Salem

[Michael W. Clark]

Good information above. I bought a 220V 2-pole, single throw switch for my air compressor from HD for about $15 IRC. I don't know what your switch looks like on your saw, but my Delts BS has a pushbutton switch that looks like those sold at Grizzly and Rockler. You can buy 220V versions of these that may fit your saw.
Mike

[Peter Kelly]

Return the 277v switch. It is a 3-way switch and meant for lighting circuits not electric motors.

For a bandsaw, you want:
http://www.mcmaster.com/#standard-mo...itches/=hqmw9q
Indoor enclosure single phase manual motor switch. McMaster part #7657K31. $34.60

There are also magnetic starters at the bottom of the page which are great for overload protection but are a bit challenging to wire if you don't have a lot of electrical experience.

[Rod Sheridan]

Regardless of what type of switch you purchase, it must be marked with a horse power rating to be used as a motor starter. You will need a switch rated for 240 volts and 3 HP (minimum).

The other issue is that motors require overload protection, either built in, or provided via the motor starter.

Check the nameplate on your motor, if it doesn't say "Thermally Protected" or words to that effect, you need external overload protection for your motor.

Please reply back with the motor current rating in amperes, and whether your motor is internally protected or not.

Regards, Rod.

[Michael W. Clark]

Regardless of what type of switch you purchase, it must be marked with a horse power rating to be used as a motor starter. You will need a switch rated for 240 volts and 3 HP (minimum).

The other issue is that motors require overload protection, either built in, or provided via the motor starter.

Check the nameplate on your motor, if it doesn't say "Thermally Protected" or words to that effect, you need external overload protection for your motor.

Please reply back with the motor current rating in amperes, and whether your motor is internally protected or not.

Regards, Rod.

Some of the switches from HD are horsepower rated, but Rod makes a good point about the overload protection. If the motor doesn't have this, you probably need something like Rod or Peter is recommending.


Mike

[Michael Menzli]

Thanks for the great feedback guys,

The motor is rated at 12.26 amps 14.2 sf amps 230 volts The motor does not list tefc but it has a circuit reset unit mount on it..basically a little red switch ..Im assuming this is what you guys are referring to?

This will be the only machine on this circuit.

I purchased and installed a 20amp double pole breaker with 12/2 wire . http://www.lowes.com/pd_13317-296-HO...AID=1367969726

I then installed this : http://www.lowes.com/ProductDisplay?...llow&cId=PDIO1 using 2 20amp slow blow fuses .. tested and I have 240 at the breaker.

From the breaker I want a "power switch" for the saw itself. Right now I want something local to determine if the motor will even work with the saw frame. Ive read where 3hp may be too much torque on a cheap HF frame. The wheels are cheap aluminum 14" . I do have a new link belt.

I bought this : http://www.lowes.com/pd_73267-334-30...tch&facetInfo=

I actually found what I needed wiring wise... One side will be my power from the box..the other power to the motor.

I too have 2 little ones (4yr and 5 mth) and will use the breaker on the wall every time. My Power switch will also be up on the wall out of reach.

[Rod Sheridan]

Hi Michael, that switch is only rated at 2 HP so it's not large enough for your motor.

Did you determine if the motor has built in thermal protection?

Regards, Rod.

[Michael Menzli]

Hi Michael, that switch is only rated at 2 HP so it's not large enough for your motor.

Did you determine if the motor has built in thermal protection?

Regards, Rod.

Hey Rod,

thanks for the followup.. I saw after posting that it was rated at 2hp. What is the issue with using one designed for less power? Does these get overheated ?

secondly the only thing i can find on the motor is a circuit breaker type unit. Basically it looks like a push button reset circuit ..not sure if this functions as a thermal protection or not..but assume no.

I did do a dry run last night..simply hardwiring to my "throw box" . The motor powered up, but almost too fast..it scared me ..not sure if this is typical of the motor , 240 or what....I can say the power down was fairly fast as well which I like a lot.. no vibration to speak of and very quiet. Id say its smoother then the original but have not installed a blade yet.

Im curious are there issue with simply using this throw/fuse box as my on off power? I have the secondary breaker at my main panel? If I do wire the switch Ill basically have 3 circuit breakers for one motor?/

[Rod Sheridan]

Hi Michael, the main issue with HP ratings on switches is to handle the learge starting currents without welding the contacts together.

Nothing so exciting as a machine you can't turn off.

The push button reset is the thermal overload for the motor, so you don't have to provide that in your starter.

I would go to a local electrical supply place and see what they have in manual motor starters, without overload protection..............Regards, Rod.

[Salem Ganzhorn]

I like these switches: http://www.grizzly.com/products/h8243

[Van Huskey]

By the way regarding 3hp vs the frame of the saw: the single link belt won't transmit nearly all the power of that motor so even if the torque could damage the frame I suspect the link belt would slip first.