Delta Bandsaw

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walhondingnashua

Minister of Fire
Jul 23, 2016
579
ohio
I was given a Delta model 28-303 bandsaw that can cut metal and wood. The issue is that it is 3 phase. I do not want to buy a converter because they seem very expensive. Is it possible to buy a harbor freight replacement motor that is single phase. I would just have to make sure it has the correct HP and diameter shaft.
Any advice out there?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
32,890
central pa
I was given a Delta model 28-303 bandsaw that can cut metal and wood. The issue is that it is 3 phase. I do not want to buy a converter because they seem very expensive. Is it possible to buy a harbor freight replacement motor that is single phase. I would just have to make sure it has the correct HP and diameter shaft.
Any advice out there?
If you can find one the right power rotation speed and shaft size sure. Shaft size could be worked around.
 

ABMax24

Minister of Fire
Sep 18, 2019
2,056
Grande Prairie, Alberta, Canada
Can you confirm the amperage and voltage of the existing motor?

You can get a single to three phase converter on Amazon for under $200, which also incorporates a variable frequency drive so you could adjust the motor speed as well. The one I seen is rated up to 20 amps.

No way I'd be messing with a different motor for that price
 
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walhondingnashua

Minister of Fire
Jul 23, 2016
579
ohio
I believe its 1.5 hp but having a hard time being for sure. I'm working on finding a manual to figure that out for sure.
I think I will lean towards the converter maybe. I have to admit, that seems a little intimidating to me but I'll do my research.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
32,890
central pa
I believe its 1.5 hp but having a hard time being for sure. I'm working on finding a manual to figure that out for sure.
I think I will lean towards the converter maybe. I have to admit, that seems a little intimidating to me but I'll do my research.
If it's only 1.5 I would just swap out the motor.
 
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ABMax24

Minister of Fire
Sep 18, 2019
2,056
Grande Prairie, Alberta, Canada
A Digital Phase Shifter creates a second output for use in the electric motor. It shifts the phase enough to allow the motor to start and operate. Almost all that I've seen only output on 2 phases, meaning your 3phase motor will only make 70% of nameplate hp as one phase is unused.

VFD's (Variable Frequency Drive) will output on all 3 phases and generally allow a motor to operate at 100% of nameplate hp. The variable part is they allow different frequencies to be output so you can change the rpm of the motor, typically with an analog dial or through menu buttons. Most can be programmed with soft start to slowly wind up the motor, instead of the abrupt start of just switching the motor direct to grid power.

A DPS is simpler, but honestly I'd just replace the motor if you intended to go that route.

I'm also assuming you have access to 220volt single phase to power the VFD and the motor is 220volt 3 phase and not 460volt or something like that.
 
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walhondingnashua

Minister of Fire
Jul 23, 2016
579
ohio
My garage can handle 50 amps but I have no 220 hook ups. The converter units I have been looking at on amazon look like the just plug into a standard 110 socket.
 

peakbagger

Minister of Fire
Jul 11, 2008
8,487
Northern NH
Its great saw, one of the last that were built in the US. Its a pretty common motor. I would give Grizzly a call as I think they sell clones. BTW, plan on buying new "tires" for the wheels and I recommend ceramic guide blocks. My guess is less than $300 for the motor. You really do not get a lot of advantage with a variable speed motor unless you plan to cut a lot of steel which can benefit from a lower speed. Then again check out Amazon Warehouse as they usually have various phase converter and single phase drives listed as returns for 30% savings.
 

Ashful

Minister of Fire
Mar 7, 2012
19,581
Philadelphia
I have a 10hp rotary phase converter I've been meaning to unload. PM me if interested. It's a serious bit of kit, probably above UPS weight limits, but we could ship in a few boxes. It isn't the cheap $200 Amazon static phase converters, but a true balanced-phase inertia rotary unit, although I'd be fine selling it at $200 with an idler motor (I have no need for it anymore). I think the idler I have for it is a 900 rpm 7.5 hp unit, as I usually tried to find low-RPM motors to use as idlers, but I'd have to double-check that.

That said, I eventually converted each of my 3-phase machines to single phase. Big single-phase motors aren't cheap (I was dealing with 5 hp vintage stuff, so... 400 pound motors), and direct drive conversions are the stuff of nightmares. But if your machine is belt drive, it's a pretty easy matter.

Do note that bandsaws do NOT play well with regular cap start induction motors, which make up about 95% of modern single phase AC motors. Most want an RI motor to handle the starting torque of a bandsaw. They're out there, but they're not cheap!
 

walhondingnashua

Minister of Fire
Jul 23, 2016
579
ohio
Does 7 HP sound about right for this unit? It does not have the label anymore and I am doing my best to find any information on it. The motor it has works fine from what I was told and I do just need the converter. However, I do not have 220. Do these converters work off of 110?
Sorry for all the questions. I am very ignorant on this topic.
 

blades

Minister of Fire
Nov 23, 2008
3,985
WI, Leroy
The converters need 220-240 V single phase input. ( 2 hot and a neutral) Digital converters will not always work with some types of motors. ( can't remember which ) Static will but you lose apx 30% of hp, Rotary units will also- pricy but no real hp loss. Static types are not great for start stop runs like an air compressor or saws unless you run an idler motor continuously which basicly makes almost a rotary unit. Always size converter above what you need - start up current draws are way higher than running amps.
 

EatenByLimestone

Moderator
Staff member
You're going to have trouble running 7hp off 110v. Your wall outlet isn't going to handle that draw. You'll need a dedicated 220 line.
 
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Ashful

Minister of Fire
Mar 7, 2012
19,581
Philadelphia
I've never even seen a 7hp bandsaw, and I've worked on them up to 36". A 7hp bandsaw would be a monster! I presently own a 32" running on 3 hp.

Rotary phase converters are the way to go, if you need 3 phase in a home shop. Running an idler, or even additional 3-phase motors on the same circuit (they all add to "idler") is the way to overcome startup load, by inertia.

As to cost, yes... not cheap. I think I spent over $1k on each of mine, and that was using mostly buying surplus parts.
 

Ashful

Minister of Fire
Mar 7, 2012
19,581
Philadelphia
You're going to have trouble running 7hp off 110v. Your wall outlet isn't going to handle that draw. You'll need a dedicated 220 line.
FLA = 80A on 115V single phase, 40A on 230V single phase.

I actually had a 5hp single phase motor that I ran once on 115V, just as a test. It was made by Century in the 1920's, as best as I could figure, and had FLA = 56A at 115V. As you would expect, the start-up current was much higher than that, but not so bad as a modern cap start induction motor, since it was an RI type with brushes that would lift off when it reached speed. Amazing motor, but it weighed 400# and was the size of a modern washing machine, so I sold it with my old table saw (which weighed 2200# and was the size fo a VW beetle).
 
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xman23

Minister of Fire
Oct 7, 2008
2,597
Lackawaxen PA
Are you sure you don't have 240 VAC single phase in your panel? Whats the name plate data of the 3 phase motor? Is this a huge industrial band saw? I think a motor maybe cheaper.

You can run 240 single phase into most (rectifier front end required) VVVF ( variable voltage variable frequency) drives. The output will be 240 3 phase. Since your not feeding the drive with 3 phase, it's output current rating is reduced by 35%. So the drive needs to be oversized. Since the motor does not start under load, that can help with the drive size needed. But this does work.
 
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walhondingnashua

Minister of Fire
Jul 23, 2016
579
ohio
Like I said, I don't have a lot of information to go on and 7 HP seemed like way to much. Hard to interpret what the old stickers all way. I can run an independent 220 line if I have to. There is plenty of room in my panel for anything really. Whether I need 110 or 220, it's going to get its own dedicated circuit.
 

Ashful

Minister of Fire
Mar 7, 2012
19,581
Philadelphia
If pulling wire in/for a shop, I can't recommend highly enough just doing all 20A multiwire branch circuits using 12/3+G. I have a few 30A and 50A circuits for big stuff, but the rest of my shop is all wired with 20A multiwire to 2-gang boxes, with a pair of 115V (NEMA 5-20R) receptacles in left slot and a pair of 230V (NEMA 6-20R) on the right slot. I alternate which hot feeds each of the 115V's, going around the shop, with 4 receptacles on each wall and each wall being a different circuit. Makes it real easy to plug any 220V piece of small equipment in anywhere (eg. 12" planer or bandsaws up to 20"), or to run numerous 115V items (eg. shop vac + router) at the same time.

How 'bout posting a photo of the tag on the motor? Do note that there are some motors made 1990's into early 2000's that might be 1.25 hp but labeled as 7 hp. I own a CH compressor and a JET bandsaw, both of which fell into this bit of manufacturer specmanship, a practice which I believe might have been outlawed in the years since. If you have any doubt about the true horsepower of your motor, go off the FLA, as the standardized tables are widely published.
 

EatenByLimestone

Moderator
Staff member
Checking amps off the tag will let you know if you have marketing based hp numbers. Figure you need 15 amp/hp.

I put a sub panel in my garage/shop to make wiring easier.
 

Ashful

Minister of Fire
Mar 7, 2012
19,581
Philadelphia
Figure you need 15 amp/hp.
Not a terrible number for 115V operation, actually. It holds true around 1hp, anyway.

Fractional-hp motors draw more amps/hp (up to 25A/hp at 1/6 hp), and larger motors draw less (10-11 A/hp for 3hp and up), and half all those numbers for 230V operation.
 

walhondingnashua

Minister of Fire
Jul 23, 2016
579
ohio
I guess it's only 3/4 HP. I am assuming that I can find a 3/4 HP replacement motor that will run at those rpms and still be 110v.

saw.jpg saw full.jpg
 

EatenByLimestone

Moderator
Staff member
That’d be no problem to run. You can find that motor on any appliance.

Edit: thought it was 220 at first.
 
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EatenByLimestone

Moderator
Staff member
But there are lots of old, used motors laying around. Just in my basement, lol


Those are all scrap motors . It’s a grab them when you see them. They can be used to make grinders, power a disc sander, etc,

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