Startrite 352s bandsaw phase conversion 3 phase to single help

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Geoffo

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So for a single phase replacement, a 2 pole 2840-3000RPM, TEFC
motor with suitable shaft which fits the pulley, seems like it might be one choice?

Can we see the mounting, as it could be foot, face or flange mounted, should one want an quicker or less bothersome installation.

On the other hand if Geoffo wants to retain the function for cutting differing materials...
and sees some dual voltage motors going cheap...
Which pole motor should be used, from what I've seen on different machines, a 4 pole slower motor seems the choice for most things not a fixed speed.

Whats the issue if one chose to run a 4 pole motor (around half the speed of 2 pole)
with an inverter at 100hz?

Is there some torque issues at double the rated speed of the motor?
Is this an application for having a fancier vector drive?

Thanks
Tom
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Ttrees

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That looks like a flange mounted induction motor TEFC (totally enclosed fan cooled)
Of what class, I'm not to up to speed on that.
The shaft size might be 24mm which I believe is the standard or should I say most common on some motors of that size.
A smaller motor might have a 19mm, and larger motor too big.
There is information about that and frame size which is likely in Bob's write up also.
The others can advise much better on that what I know about motors.

A piccy of the motor nameplate if not absolutely identical to the above one might be useful,
if you happen to see a 240v with a triangle or "D" for delta low voltage configuration,
would make hooking up a VFD easy peasy.

Tom
 

Ttrees

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Seems the same deal as the other motor, as in seemingly unsuitable for use with a VFD from what others are saying.

Have you decided if you want to cut metal or plastics with this machine, aswell as wood?

If your just cutting timber, then a single phase replacement would be simple enough.
I'd be looking for a 2hp motor (flange mounted TEFC) with 19mm shaft,
but you might want 3hp if you're going to be using a 16a blue plug.
The faster speed more suited for timbers, so it would be a 2 pole/2740 RPM motor,
of what rating of duty or class... I'd have to check Bob's write up that I linked.

Since the wheels aren't that large or as heavy as cast iron, which I believe they aren't.
and depending if youre running machines from a 13 plug, you might be worried about blowing fuses, cold weather reputed to be worse for that, so playing it safe wouldn't be a bad thing and sticking to 2hp, although I'd like to see what other folks say with that saw.

The other option is to find a cheap dual voltage motor, which can run on household 240 volt leccy
which will look like 220 or 240v beside either a triangle, delta or just a D noting it.
If on a 13a house plug, then you might be pleased to read that you can go higher with the hp/kw
as a VFD will take care of that pesky starting surge, fuse blows or MCB nuisance trips at the CU (fusebox) as its easy peasy adjustable soft start to suit the supply you're using.

I would like to see what folks recommend, two or four pole, should you wish to cut other stuff with it.
Sorry I can't be of more help

Tom
 

Craig22

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FWIW I used a digital converter on my Wadkin BRA14 radial arm saw. That is a 1HP 3 phase motor with a 1" shaft of a particular length with a left hand Acme thread - so replacement with a 1 phase motor was not an option.

I used a Drives Direct unit. They mainly sell through eBay now. IIRC mine was around £250 when I bought it ten years ago, about. It has worked without missing a beat ever since. You can also set speed ramp up and braking.

The 2HP unit is here 2 HP DIGITAL 240V to 415V 3 PHASE INVERTER CONVERTER LATHE MILL DRILL | eBay . Looks like the price has gone up. Surprise, surprise.

Bear in mind if you go for a 1 phase replacement for the Startrite band saw that one phase motors vibrate more than 3 phase ones, and lack of vibration is a key attribute of accuracy in a band saw.
 

Geoffo

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Seems the same deal as the other motor, as in seemingly unsuitable for use with a VFD from what others are saying.

Have you decided if you want to cut metal or plastics with this machine, aswell as wood?

If your just cutting timber, then a single phase replacement would be simple enough.
I'd be looking for a 2hp motor (flange mounted TEFC) with 19mm shaft,
but you might want 3hp if you're going to be using a 16a blue plug.
The faster speed more suited for timbers, so it would be a 2 pole/2740 RPM motor,
of what rating of duty or class... I'd have to check Bob's write up that I linked.

Since the wheels aren't that large or as heavy as cast iron, which I believe they aren't.
and depending if youre running machines from a 13 plug, you might be worried about blowing fuses, cold weather reputed to be worse for that, so playing it safe wouldn't be a bad thing and sticking to 2hp, although I'd like to see what other folks say with that saw.

The other option is to find a cheap dual voltage motor, which can run on household 240 volt leccy
which will look like 220 or 240v beside either a triangle, delta or just a D noting it.
If on a 13a house plug, then you might be pleased to read that you can go higher with the hp/kw
as a VFD will take care of that pesky starting surge, fuse blows or MCB nuisance trips at the CU (fusebox) as its easy peasy adjustable soft start to suit the supply you're using.

I would like to see what folks recommend, two or four pole, should you wish to cut other stuff with it.
Sorry I can't be of more help

Tom
Is there any chance of speaking with you on the phone Tom
 

Fitzroy

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Geoffo,

Not trying to muddy the waters as I think I'm saying the same as Tom. I see you have two main options:
- Replace with a single phase, single speed motor (2 pole / 3000 rpm), this will give you one cutting speed.
- Replace the a three phase motor and a VFD, this will give you a range of cutting speeds.

Whether you pick the single phase route or the three phase you will need a flange mounted (B5 Specification) motor.

There are a number of other things you'll need to then workout.
Single Phase option
  • New switch gear will be required.
  • You could buy another sized pulley for the motor, this would give you a second speed at the faff of having to change it.
  • Motor power increases the in rush on start-up for and may require a higher current breaker/supply. My 1.5kw (2hp) thicknesser will trip a 13A supply on a cold morning (<5Celcius), as it spins up the heavy cutter block. I'd not go above 2HP on a 13A plug
Three phase
  • You'll need a 240V three phase motor so it can be used with a VFD from the 240V mains
  • You'll need an isolator to go between the plug and the VFD.
  • You'll need a housing for the VFD, and external switching if you want to start/stop the machine without pushing the tiny buttons on the VFD.
  • Motor power increases both motor cost and VFD cost.
Single or Three phase
  • Motor power decision, more power is more expensive.
  • You'll need to think about if you want any door interlocks to continue to work, and then wire them into the new set-up.
  • The shaft size on the motor is normally related to the motor power, often the move from a 19mm shaft to a 25mm shaft is in the 1.5-2HP range. If you change shaft size you will need a new pully, these are easily bought and relatively cheap approx. £20 for pully and taper lock bushing.
Personally I would go the single phase route, it'll be the simplest and cheapest.

Fitz,
 

Ttrees

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Is there any chance of speaking with you on the phone Tom
Here all the time Geoffo, better to get answers from others as I'm just a Joe Soap, who knows nothing about electrics, apart from hooking up a VFD to a dual voltage motor,
and a wee bit about VFD's, should you have no choice apart from a cheapie inverter, (highly frowned upon by some)
or have want for a certain features like a auto shutoff fan, instead of one humming all the time.

Jack Forsberg
(Jack English machines) on youtube, has some vidoes on the subject of features, as he gets custom specified VFD's specially sent over from the Far East.

Everything I know installation wise is acquired knowledge from this forum and Bob Minchin's (myfordmans) helpful document.


Should you be shopping for motors that you don't want to publicize openly, you should be able to message me, (maybe there's a 3 post requirement,for "conversations")
It won't go unnoticed, as that's the spirit of these places.

Likewise if looking for advice on setting things up, on this thread or even a new one
regardless which motor you choose, folks will know you might want a hand with this and will keep an eye on it to walk you through.

You will get the info you require, if you state the work you plan on doing with the saw.

To give you some perspective on your choices, I can give my 2 cents.
For what it's worth I fitted a pot (potentiometer) like you see on electric guitar tone controls to give variable speed using a cheap huanyang VFD, on my 24" bandsaw.
I didn't use the variable speed in the end, took it off and not missing it one bit.

(this paragraph below is why I wouldn't choose a cheapie VFD for variable speed)
Basically saying better to get a good VFD if intending to use a pot.
That likely changes things to make it a more expensive affair,
not saying if I needed to cut a lot of plastic or something else, that I couldn't manually type in
25hz and lock parameters (half speed of our 50hz power supply in Europe,
and keep an eye on the heat, as not efficiently cooling at that speed.

Why not a cheapie with a pot?
(The lights dimmed whilst adjusting, as they do when I use a heat gun or something else consumptive, (badly wired system in rented house)
That never happens even on startup or heavy cutting on this large saw.
Turns out the old Huanyang (one could call these one of the first of the cheapies)
It didn't like the use of a pot, and used to trip out.
Normally this tripping out is just a case of opening the box and hitting stop to reset,
looking back it must have been the pot doing this, as I haven't needed to touch either of my VFD's since.
The last straw was when it tripped, and couldn't be reset by a button, found out there is another reset inside (being aware that these things hold a charge after being unplugged! NO going near it until its powered down)
Took me ages to find that out, and I would take a wild uneducated guess its the same deal with any cheap VFD.
Saying that, a Jackified version could well be designed differently, and somethings could be done differently now on all, if my quiet VFD is anything to go with.
That doesn't mean that a knockoff of Jack's using cheaper parts wouldn't be just as problematic)


I've likely complicated your thread, so I'll stop now
It just seems to me you're on the fence about whether you want variable speed or not.

All the best
Tom
 

Fergie 307

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I've not worked with two speed 3 phase motors so take my advice as you see fit. 3 phase motors usually have 3 wires going to them from the control gear so I presume as it was two speed thats where the 6 wire come into the situation. What you need to do is pick 2 of the black wire for the motor wiring use a meter to find the two ends of each wire which you want to use, you could cut the other back so they don't cause a short but better to tape the ends. Should be a simple exercise after that. My older 352 is also ex school and 3 phase run off a phase converter. Good luck with the conversion and come back if you need more help.
For the relatively trivial cost I would remove the original wiring and replace with the proper colours, will make life much simpler and avoid possibly dangerous confusion in future. The two speed switch is now going to be redundant, so you can lose the wiring attached to that. Either leave the switch in place or remove it and put a grommet in the hole. Then wiring up the new motor should be pretty straightforward. If you need to source cable then I would think any local electrical contractor will sell you a few feet of suitable conduit type cable so you can 're use your armoured sleeve. Keep all the bits as if you ever sell it someone might want to convert it back.
 

Fergie 307

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Does nobody bother to read the original post. The guy doesn't want to hear umpteen options on how to do it. He's bought the bits and just wants some help on how to wire it up.
 

Fergie 307

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Sorry, realise it might be straightforward to me but maybe not for you. Not sure from the original post exactly what you have in the way of switch gear. You should have a no voltage release switch. This should be clearly marked with two sets of in and out terminals. So your plug goes to the in terminals, then you need two sets of wires from the out terminals, one to the motor, which should also be clearly marked, and another set to the appropriate terminals on the transformer for the lamp, making sure you use the 220/240v option. Not sure what overload device you have so can't comment on that, but Again if new it presumably comes with some documentation which should tell you how to wire it. One thing to bear in mind is if the armoured conduit is metal, which I assume it is, then this needs to be earthed. Originally this was probably done through metal fittings, enabling it to share the earth with the cabinet itself. If you change things it's easy to overlook this. If I'm doubt just solder a wire to the armoured outer inside the box and earth it by connecting it to the cabinet. The cabinet itself must be earthed, and there will be an existing connection for that. Much of the existing nest of wires is to do with the two speed operation, so I can understand why that might be confusing. Might make it easier to just remove it all. If in any doubt I dare say the people who supplied the kit will help you. If you still don't feel confident, then probably best to get an electrician in to do it for you. If you mount the motor, switch etc so all they have to do is wire it up then shouldn't be too expensive, and probably worth it for peace of mind.
 

Fergie 307

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So for a single phase replacement, a 2 pole 2840-3000RPM, TEFC
motor with suitable shaft which fits the pulley, seems like it might be one choice?

Can we see the mounting, as it could be foot, face or flange mounted, should one want an quicker or less bothersome installation.

On the other hand if Geoffo wants to retain the function for cutting differing materials...
and sees some dual voltage motors going cheap...
Which pole motor should be used, from what I've seen on different machines, a 4 pole slower motor seems the choice for most things not a fixed speed.

Whats the issue if one chose to run a 4 pole motor (around half the speed of 2 pole)
with an inverter at 100hz?

Is there some torque issues at double the rated speed of the motor?
Is this an application for having a fancier vector drive?

Thanks
Tom
From my experience you are better to use a fast motor and slow it down, than running a slow one at double speed. I have a Harrison lathe which uses a 2800 rpm 240v 3 ph, 3hp motor. I use a Huan Yang 4.2 inverter and have a switch to run it at full or half speed, to imitate the original two speed motor. Works a treat, and the motor doesn't appear to mind prolonged running at half speed, certainly no issues with overheating etc which is a concern raised by some people.
 

Geoffo

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Geoffo,

Not trying to muddy the waters as I think I'm saying the same as Tom. I see you have two main options:
- Replace with a single phase, single speed motor (2 pole / 3000 rpm), this will give you one cutting speed.
- Replace the a three phase motor and a VFD, this will give you a range of cutting speeds.

Whether you pick the single phase route or the three phase you will need a flange mounted (B5 Specification) motor.

There are a number of other things you'll need to then workout.
Single Phase option
  • New switch gear will be required.
  • You could buy another sized pulley for the motor, this would give you a second speed at the faff of having to change it.
  • Motor power increases the in rush on start-up for and may require a higher current breaker/supply. My 1.5kw (2hp) thicknesser will trip a 13A supply on a cold morning (<5Celcius), as it spins up the heavy cutter block. I'd not go above 2HP on a 13A plug
Three phase
  • You'll need a 240V three phase motor so it can be used with a VFD from the 240V mains
  • You'll need an isolator to go between the plug and the VFD.
  • You'll need a housing for the VFD, and external switching if you want to start/stop the machine without pushing the tiny buttons on the VFD.
  • Motor power increases both motor cost and VFD cost.
Single or Three phase
  • Motor power decision, more power is more expensive.
  • You'll need to think about if you want any door interlocks to continue to work, and then wire them into the new set-up.
  • The shaft size on the motor is normally related to the motor power, often the move from a 19mm shaft to a 25mm shaft is in the 1.5-2HP range. If you change shaft size you will need a new pully, these are easily bought and relatively cheap approx. £20 for pully and taper lock bushing.
Personally I would go the single phase route, it'll be the simplest and cheapest.

Fitz,
Hi fitz
I am going to change to single phase I do a bit metal work but most of the time it is wood I’ve been getting a lot of oak and milling it and making mantles 6x6 6x5 inch some bigger using a jig and gide I made up for my little chainsaw . Got a static phase converter off a friend as a present as he new I was after a saw so I could go for a 240 or 3 phase not a problem the converter did not work and this is were I am today still scratching my head thanks for getting back to me 👍
 

Myfordman

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To cut steel you need around 100 feet per second, wood cutting will need in the region of 3000 FPS
An inverter will not give you 30:1 range alone without motor overheating problems and possibly too little torque to boot.
You will need to be able to drop the speed by say 4 or 5:1 by mechanical means and do the rest with the inverter.
Dont forget that if you have a dahlander 2 speed 3 phase motor at the moment, this cannot be configured for 240v inverter.

If you like challenges then go ahead or flog this and get a back geared bandsaw that is designed for both metal and wood.
Something like a startrite 18-s-10 would be a good choice.
 

Geoffo

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To cut steel you need around 100 feet per second, wood cutting will need in the region of 3000 FPS
An inverter will not give you 30:1 range alone without motor overheating problems and possibly too little torque to boot.
You will need to be able to drop the speed by say 4 or 5:1 by mechanical means and do the rest with the inverter.
Dont forget that if you have a dahlander 2 speed 3 phase motor at the moment, this cannot be configured for 240v inverter.

If you like challenges then go ahead or flog this and get a back geared bandsaw that is designed for both metal and wood.
Something like a startrite 18-s-10 would be a good choice.
I was told a 2 hp sing phase 3000 rpm motor and switch gear and other stuff so I can decrease and increase the speed can this be done thanks. Geoff
 

Fergie 307

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Myfordman makes a good point. You can get away with higher speeds for aluminium and plastics, but will still need to slow it down. Not familiar with the machine but assume it's belt drive, so you can change the size of the pulleys to slow it down. Whether that might need modifications to the belt guard etc is another matter. All depends on exactly what you want it to do really. I only really use my Kity for metal, and have slowed it to about half speed by fitting different pulleys.
 

Myfordman

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I was told a 2 hp sing phase 3000 rpm motor and switch gear and other stuff so I can decrease and increase the speed can this be done thanks. Geoff
No you need 3 phase motor to do speed control properly. The no of motor poles you need depends on the design of the saw.
 
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