HF 4x6 bandsaw - universal or induction motor?

Volts x Amps = Watts
Assume your line voltage is 120 (it's usually betwee 115 and 123 in the US).
120 x 6.4 = 768. There are 745.6 Watts per horsepower so, you're motor is just a tad bit more than 1HP.


I beefed-up the base on mine a little and raised the height so I don't have to work like a cave man. Pic isnt too great but it's just some angle iron bolted to the corners following the angle of the existing base. Eliminates the tip-over problem...



twstoerzinger said:
I just bought a new one from HF a couple of months ago.
Now the color is a maroon-red.
The motor is TEFC cap-start, 4 pole rated at 1725 rpm.
The nameplate says 1 HP, but the FLA is 6.4 amps. So, it's really about 1/2 HP.
Not sure how the Chinese come up with 1 HP.
Once you get the belt guard properly fitted so it doesn't rattle, the saw is fairly quiet.
It still amazes me though, how the Chinese get their motors to hum as much as they do.

I was a little surprised to find the gearbox free of chips and filled with clean gear lube.
I left off the wheels so that I am not temped to move it that way.
Once leveled and in place, I feel the sheet metal stand is OK.

I went through the usual tear-down, cleaning, and alignment before use.
I have already cut a fair amount of steel with it. It actually cuts pretty square.
Buy a couple of good quality blades - the one that comes with it is pretty weak.

Oh - be sure to install the safety pin on the back every time you leave the saw not running.
If the pin is not installed, it is easy for someone to lift the saw, have it go over-center and tip over on the floor.
Hasn't happened to me yet, but I can see why many people warn about this feature.

Terry S.
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My gearbox was clean also. I added wheels to mine but they will tip VERY easy. Don't ask how I know.



bedwards
 
I'm in the process of bolting it down here to a HF heavy one drawer service cart.
The wheels are outside the cart, stabilizing it. They all roll and can be locked.
You simply use a hack saw to cut away part of the handle from the legs on one side to allow the saw to fit.

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Ray C said:
Volts x Amps = Watts
Assume your line voltage is 120 (it's usually betwee 115 and 123 in the US).
120 x 6.4 = 768. There are 745.6 Watts per horsepower so, you're motor is just a tad bit more than 1HP.


I beefed-up the base on mine a little and raised the height so I don't have to work like a cave man. Pic isnt too great but it's just some angle iron bolted to the corners following the angle of the existing base. Eliminates the tip-over problem...
Click to expand...

I have to respectfully contest the motor HP calculation.

Actually, Volts * amps = watts only works with DC or with pure resistive AC loads.
An electric motor is a big induction load, so you have to use volts * amps * power factor * motor efficiency = watts output on the shaft.
With 3 phase motors, an additional factor comes in.
Motor efficiency for small, single phase motors like this often do not exceed 80% with power factors around 70 - 80%.
So the equation for single phase AC motors is HP = V * A * eff * PF / 746

Typical FLA (full load amps at rated shaft power) for a 1 HP motor is around 16 amps.
6.4 FLA amps on the Harbor Ft motor gets you between 1/4 and 1/3 HP on the shaft (and a little less than that after you go through the gear box).

So far I have ran my saw at the lowest speed of the 3 belt settings.
After an hour of cutting steel, the motor is only warm to the touch.
At this speed, it takes a while to cut through something, but the saw blade, the work piece and the motor all remain cool.
So far, I have kept my saw at the delivered height. I sit on an inverted 5-gal bucket when loading and setting up the saw.
Gives me a chance to rest my back after standing.
I let it run on its own while cutting, but I stay in ear-shot in case it develops a problem. So far there have been no problems.

Terry S
 
the cap in mine is a run cap, It went bad and I had a start cap the same value and it wouldn't start. I also had a run cap and it works fine with the run cap in it.

It even says Motor Running Capacitor on it and it is a 40uf 250VAC.

Paul
 
I took a quick look at the motor on the HF bandsaw and did a few measurements with a kill-a-watt power meter. Under running load while cutting a piece of barstock, the power factor was .87 and the current was 3.3 Amps. The motor is listed as class A. Yes, HP of a motor takes several things into consideration and they can also be temperature sensitive. I believe the NEMA classifications set the boundaries. Initially, I thought that motor was poor quality but the more I look at it, and think of the service I've gotten from it, it seems pretty decent and if anything, is oversized for the application. It's the same motor HF puts on their larger saw so, they probably keep them the same to make life less complicated.

Anyhow, this summer, I had a bunch of cuts each took about an hour (steel I-beams). It only got warm to the touch. That leads me to believe it's fairly efficient. I had an older Marathon motor on a lathe and after a good while, it was on the borderline of not being able to touch it. Maybe HF sells these things with different motors -but the one on mine isn't half bad at all. Anyhow, as far as the overall saw is concerned, I've gotten 2 years of hard labor out of it, and it hasn't let me down. Would I like a bigger saw? Sure. When I cut 4" stainless bar stock, it takes almost 3 hours... but for what I paid, for it, it's a keeper.

HFSawMotor.JPG
 
joe
if your thinking of buying a used hf bandsaw i would check the backlash in the gear box. the owner may not have cleaned it out and replaced the oil and they will eat the gears. the chinese recycle all their waste oil by shipping it to the world in tools lol
just my .02
steve
 
joe_m said:
It's 78.2 miles to the bigger Tucson HF, so new or used I'd be making a drive unless I had it delivered.

7HC - Those Central Machinery ones make up the majority of the other color I see. Thanks for the info.

Joe
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Might be worth considering having it delivered for the $22 it will cost, compared to an almost 160 mile round trip.


M
 
Typical FLA (full load amps at rated shaft power) for a 1 HP motor is around 16 amps.
6.4 FLA amps on the Harbor Ft motor gets you between 1/4 and 1/3 HP on the shaft (and a little less than that after you go through the gear box).


Terry S[/QUOTE]

if 1hp at 110v needs 16 amps how does my old craftsman 110v air compressor with a 5hp motor run on my 20 amp breaker? would that not need 80 amps with this math
i'm not trying to be a smart a.. i'm curious
steve
 
no it is 110v not 220 and i know it is close to 20amp because it will not run on a extension cord of any length.
steve
 
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