changing a 3 phase wall saw to single phase

[desmo11225]

And this is the fan; it appears that the screws that hold the motor to the housing are behind it and we're struggling to work out how to remove it. We've tried a make shift gear puller type arrangement with no joy. Any clever ideas would be appreciated.
Thanks

 

[guineafowl21]

Looks like permanent star. Those brown wires seem to go to the same place so I’d guess thermal switch.

The three main phase wires all appear to go to the bottom, so I’d look for the star point at the top. For example, there’s a winding wire between 10 and 11 o’clock that might be involved.

Measure the resistance between phase wires. That way, you can confirm when you’ve found the star point as it will have 1/2 the resistance to each phase wire.

 

[Myfordman]

I suspect that this motor body will be designed into the structure of the saw and direct drive on the saw? Ie no belts/pulleys - please say if it is a standrd motor as you could possibly swap it for a single phase motor.
If it is a special then you need to proceed with great caution not to damage it beyond repair. the choices are to find the star point and convert to delta - this is a skilled job then you can run from an inverter. Otherwise leave it well alone and instead puchase a converter that will provide 415v 3 phase from your 240v single phase supply. this is then just a wiring job with minimal risk.

 

[desmo11225]

I suspect that this motor body will be designed into the structure of the saw and direct drive on the saw? Ie no belts/pulleys - please say if it is a standrd motor as you could possibly swap it for a single phase motor.
If it is a special then you need to proceed with great caution not to damage it beyond repair. the choices are to find the star point and convert to delta - this is a skilled job then you can run from an inverter. Otherwise leave it well alone and instead puchase a converter that will provide 415v 3 phase from your 240v single phase supply. this is then just a wiring job with minimal risk.

 

[desmo11225]

Hello myfordman , the Holzher type 1205 mach no 1301 - 1980 is belt driven , Shaun Crump does'nt reply to the present e.mail adress , i'll write or ring him . Thank's desmo11225

 

[Myfordman]

Ok As it is a belt driven machine I'd just put a 3 hp dual capacitor start and run motor on it for the cheapest, easiest solution.

 

[desmo11225]

Ok As it is a belt driven machine I'd just put a 3 hp dual capacitor start and run motor on it for the cheapest, easiest solution.

 

[desmo11225]

Thank you myfordman , that sounds the easiest solution by far , would you reckomend a motor for it , Machine Mart is quit near to us ,what about them ???? or is there better??? and what about 2 and 4 point motors ??? we could take the motor to them that's if we could get it off and see if they could fix us up . Thank's for your help , desmo11225

 

[Myfordman]

First thing is that I would not darken the doors of machine mart. They have/had a poor reputation for handling warranty issues. Might just be my predjudice but there are better places to go where you can get expert back up.
We need to know much more about your motor. The photo you have already posted claiming to be the motor rating plate is really the machine plate as it mentions different speeds. that are higher than any induction motor can achieve on 50hz mains.
We need the actual parameters of the motor itself. Hopefully it is a metric sized motor as they are more available. for size and mounting styles see the appendices in my motor paper here https://drive.google.com/file/d/0B_GZrXNsNxTlQzd6aldlQjJtUDQ/view?usp=sharing

You need to find if it is a 2 pole (2850 rpm) or a 4 pole (1425 rpm) and get the same speed of motor. Is it face, flange or foot mounted?
Face mount has the bolt holes on a circle smaller than the motor body, flange mount has the bolt holes on a circle larger than the motor body and foot mount has feet with bolt holes.
A general photo of the motor on the machine with the belts, pulleys and mountings will help set the context for us. Don't forget you have the thing in front of you- we have never seen it yet.
Can I suggest that you remove the motor and post photos of it. This might expose a plate with the infomation we need; otherwise some more measurements will be needed.

That is your homework for now!

Bob

 

[desmo11225]

First thing is that I would not darken the doors of machine mart. They have/had a poor reputation for handling warranty issues. Might just be my predjudice but there are better places to go where you can get expert back up.
We need to know much more about your motor. The photo you have already posted claiming to be the motor rating plate is really the machine plate as it mentions different speeds. that are higher than any induction motor can achieve on 50hz mains.
We need the actual parameters of the motor itself. Hopefully it is a metric sized motor as they are more available. for size and mounting styles see the appendices in my motor paper here https://drive.google.com/file/d/0B_GZrXNsNxTlQzd6aldlQjJtUDQ/view?usp=sharing

You need to find if it is a 2 pole (2850 rpm) or a 4 pole (1425 rpm) and get the same speed of motor. Is it face, flange or foot mounted?
Face mount has the bolt holes on a circle smaller than the motor body, flange mount has the bolt holes on a circle larger than the motor body and foot mount has feet with bolt holes.
A general photo of the motor on the machine with the belts, pulleys and mountings will help set the context for us. Don't forget you have the thing in front of you- we have never seen it yet.
Can I suggest that you remove the motor and post photos of it. This might expose a plate with the infomation we need; otherwise some more measurements will be needed.

That is your homework for now!

Bob

 

[Myfordman]

ERM? blank reply ?

 

[desmo11225]

Hi Bob, I'm Des, we have taken the saw motor to a motor specialist !!!!!He says we ought to go for an inverter 2.2 kw single to 3phase inverter there are a good selection on Amazon around a £100 would they be any good ???? I also have an overall pic of the saw , which I will send to you as soon as I have help to do it , definitely by tomorrow . Thank you Bob all the best Des

 

[guineafowl21]

we have taken the saw motor to a motor specialist

Probably the best place for it...
Is he going for star point extraction, or a step-up inverter?

I would take advice from the specialist about inverter drives. For a start, you generally spec them according to full load amps, not kW/hp, and, especially if you’re going for the cheaper end of the market, it’s better to overspec the inverter somewhat.

 

[Myfordman]

Des, he is talking through his nether regions. I would engage him on a fixed price basis to get your motor running for £100 plus say an hour of his time. I wonder if he has even noticed that you motor will need a star to delta re-wire??

 

[Myfordman]

Probably the best place for it...
Is he going for star point extraction, or a step-up inverter?

I would take advice from the specialist about inverter drives. For a start, you generally spec them according to full load amps, not kW/hp, and, especially if you’re going for the cheaper end of the market, it’s better to overspec the inverter somewhat.

None of those options are going to come in at around £100 though.

 

[guineafowl21]

None of those options are going to come in at around £100 though.

No, although you can get a 3hp 240V inverter for around £90, and someone on here found a step-up type for similar money. Undoubtedly low quality.

As far as I can find out, there’s nothing for under £100, even in the cheap end, that will allow overspeccing, say 4hp or so. We’re very much gambling in the ‘buy cheap, buy twice’ area.

Des, keep us updated with your dealings with this motor man. I’d be very interested in how he deals with your machine. As above, get firm quotes and details of exactly what’s going to be done before going ahead with anything. Enquire about after-sales warranty - if he won’t put his name to the work, then it’s better to walk away and swallow the price of a decent step-up inverter once, rather than to do same after lots of hassle.

 

[guineafowl21]

For some reason the ‘edit’ function has frozen. Sorry for double post.

I highly recommend you read the link at the bottom of Myfordman’s posts. I read it for the first time a few nights ago - it will arm you with concise information that will help in dealings with this motor specialist.

 

[Myfordman]

deleted

 

[desmo11225]

Hello Bob I've tride to read your motor paper but I ca'nt get it , I have an iMac does that make a difference . All the Best Des

 

[Myfordman]

Hello Bob I've tride to read your motor paper but I ca'nt get it , I have an iMac does that make a difference . All the Best Des

It should just be a straightforward download for the link but I have attached a copy to this post