motor changing??

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kpsjoiner

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hi, i have the chance of a sedgwick spindle moulder sm3, but its 3 phase, could i buy a new motor and convert it to single phase? is it easy/possible? i have no idea with things like this.. thanks kevyn
 

tool613

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kpsjoiner":24jqfqy9 said:
hi, i have the chance of a sedgwick spindle moulder sm3, but its 3 phase, could i buy a new motor and convert it to single phase? is it easy/possible? i have no idea with things like this.. thanks kevyn

with a vfd there is no problem running a 3 phase motor. i do not know over there but they are way cheaper than a new single phase motor. 3 phase on a shaper with a vfd is the way to go. you get speed control, breaking ,forward and reverse. you can over run the speed for router bits, have 3 wire control. an on and on and on. vfd are so easy to wire a monkey could to it. one thing is the motor voltage need to be in the 208,220,230,240 range.
i would get a vfd shipped and be done with it. here is one that will give just over 10.5 a of power. for $185. single phase input.
http://www.factorymation.com/s.nl/it.A/ ... ategory=32

vfd do a lot more than just phase conversion. really they are easy to wire . single phase power to the vfd for there to the motor. the remote station 3 wire controls can be hard but they don't have to be. you can just use the key pad.



jack
 

tjwoodms

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shouldnt be to much of a problem on a sm3
you may need to fit a new starter and thermal overload. Have a look at the contactor if it has a 415v coil it will need to be replaced but if it has a 230v coil you should be ok.

If you take the details from your existing motor frame number shold be sufficient and you need to know the shaft size. Any decent rewinders should be able to supply you with a motor that will do the jon
 

tisdai

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My previous table saw was a 3 phase machine and when connected to the normal 240 volt socket it would only turn a couple of times and then stop. I ended up having a dedicated breaker installed in the consumer unit just for that, not sure now what size breaker it was.

If i was you i would Follow the link in the footer of Bobs / 9fingers reply to you.

It has a wealth of information about what you are looking for.

Cheers

Dave
 

9fingers

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tisdai":2rlj2m3c said:
My previous table saw was a 3 phase machine and when connected to the normal 240 volt socket it would only turn a couple of times and then stop. I ended up having a dedicated breaker installed in the consumer unit just for that, not sure now what size breaker it was.

If i was you i would Follow the link in the footer of Bobs / 9fingers reply to you.

It has a wealth of information about what you are looking for.

Cheers

Dave

I also have this flow chart as an unpublished work in progress which I **think** is correct but might still have the odd error in it.

Image1-1.jpg


Bob
 

xy mosian

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Bob, I am no expert, but I wonder if it was intentional to question motor power twice?
3rd. line down to the right, and 6th. line down to the right.

HTH
xy
 

tool613

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bob

thats a great flow chart. you know how us woodworkers need to visualizes. the vfd 3 phase combo is just the best thing sense the mechanical drive . i have in some cases taken out single phase motor for a vfd 3 phase combo speed control and or breaking. for a drill press i did it and it is great. i never change the belts. the vfd has almost replaced the mechanical drive. i got 4 vfd in the shop and am ordering another. really the best thing in years,and every one knows real tools are 3 phase



jack
 

9fingers

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xy mosian":19xb8ps4 said:
Bob, I am no expert, but I wonder if it was intentional to question motor power twice?
3rd. line down to the right, and 6th. line down to the right.

HTH
xy

Yes it is deliberate ( see the 4 and 5 hp related assumptions).

However your question has revealed an error in my diagram

which should be thus

motor1.jpg
 

9fingers

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tool613":2xkc6xnc said:
bob

thats a great flow chart. you know how us woodworkers need to visualizes. the vfd 3 phase combo is just the best thing sense the mechanical drive . i have in some cases taken out single phase motor for a vfd 3 phase combo speed control and or breaking. for a drill press i did it and it is great. i never change the belts. the vfd has almost replaced the mechanical drive. i got 4 vfd in the shop and am ordering another. really the best thing in years,and every one knows real tools are 3 phase



jack

I'm with you all the way Jack when it comes to VFDs

I have 6 installed in my workshops and about another 5 on the shelf of various types for future use. Whenever I see one being sold cheaply, I tend to buy it and have supplied numerous ones to forum members over the years.

I even put one on my cyclone dust extractor as the blower is mounted in the roof trusses and I wanted to be able to tune out any resonances when it was running.
They are also every good for running powerful machines on UK plugs which have fuses built in and often don't like the starting surge of single phase motor.

Bob
 

tool613

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bob are you there resident go to guy. for phase conversion and motor controls, was that you that did up the pdf?


you can input single phase into most 3 phase vfds by derating the unit by 1/3 to 1/2. single phase input to 3 phase vfd is done all the time and more and more manufacture are providing the derated value with single phase input. a rule of thumb is 2/3 power out for a three phase vfd feed with single phase. so a 10Hp vfd three phase in feed with single will give you power to run about a 7.5hp motor. what i have found is that a vfd up to 3hp is cost effective for phase conversion. as the price goes why up after that. but most vfds can be feed single phase power.
if your chart is to reflect what to do for phase conversion than i think it is great. you could add that larger units are available but the cost goes way up after 3hp





jack
 

9fingers

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tool613":337db8ls said:
bob are you there resident go to guy. for phase conversion and motor controls, was that you that did up the pdf?


you can input single phase into most 3 phase vfds by derating the unit by 1/3 to 1/2. single phase input to 3 phase vfd is done all the time and more and more manufacture are providing the derated value with single phase input. a rule of thumb is 2/3 power out for a three phase vfd feed with single phase. so a 10Hp vfd three phase in feed with single will give you power to run about a 7.5hp motor. what i have found is that a vfd up to 3hp is cost effective for phase conversion. as the price goes why up after that. but most vfds can be feed single phase power.
if your chart is to reflect what to do for phase conversion than i think it is great. you could add that larger units are available but the cost goes way up after 3hp





jack

Well sort of :wink: The pdf is all my fault!

I take your point about feeding single phase into a three phase inverter with suitable de-rating but that does not work for UK supply voltages

We have 240 single phase and 415 three phase supplies so three phase UK inverters expect 415v input an flag under voltage errors if 240v single phase is connected. Now it is possible to use an transformer (isolating or auto) to step the 240v up to 415v, feed a three phase input inverter (suitably de-rated) but that is getting quite expensive unless you have the transformers already.

If the inverters are opened up and extra rectifiers and reservoir capacitors added, it is possible to do away with de-rating and that should work for Canadian supplies too. All that is needed is sufficient current handling from the rectifiers and sufficient reservoir capacitance to keep the DC ripple within required limits. Quite dangerous voltage levels when playing with these so care and knowledge required.

Not sure about Canadian power distribution. How do you guys get enough volts to power your 3 phase inverters?

Cheers

Bob

ps Note to self: Must add comment to the next edition of my motor write up to stress application to EU based power systems only.
 

ondablade

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Hi Bob. Not sure if/how it fits in, but judging by my 3 phase Agazzani bandsaw saga there's the odd 400V delta wound motor about that is dual voltage, but which as a result would need even higher voltage to run it in star configuration...
 

9fingers

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Good point Ian,

I should change my flow chart to read 240/415 rather than dual voltage.

I presume your motor is marked 415/600 (approx) on the rating plate.
From memory it was a 5hp which I suppose is just about at the lower end of the power range to find a 415 delta 600 star.

I've not played with >5HP machines. Digit (Roy) is the main man round here when it comes to real power in his past life :wink:

Cheers

Bob
 

tool613

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9fingers":2sn3rtsi said:
tool613":2sn3rtsi said:
bob are you there resident go to guy. for phase conversion and motor controls, was that you that did up the pdf?


you can input single phase into most 3 phase vfds by derating the unit by 1/3 to 1/2. single phase input to 3 phase vfd is done all the time and more and more manufacture are providing the derated value with single phase input. a rule of thumb is 2/3 power out for a three phase vfd feed with single phase. so a 10Hp vfd three phase in feed with single will give you power to run about a 7.5hp motor. what i have found is that a vfd up to 3hp is cost effective for phase conversion. as the price goes why up after that. but most vfds can be feed single phase power.
if your chart is to reflect what to do for phase conversion than i think it is great. you could add that larger units are available but the cost goes way up after 3hp





jack

Well sort of :wink: The pdf is all my fault!

I take your point about feeding single phase into a three phase inverter with suitable de-rating but that does not work for UK supply voltages

We have 240 single phase and 415 three phase supplies so three phase UK inverters expect 415v input an flag under voltage errors if 240v single phase is connected. Now it is possible to use an transformer (isolating or auto) to step the 240v up to 415v, feed a three phase input inverter (suitably de-rated) but that is getting quite expensive unless you have the transformers already.

If the inverters are opened up and extra rectifiers and reservoir capacitors added, it is possible to do away with de-rating and that should work for Canadian supplies too. All that is needed is sufficient current handling from the rectifiers and sufficient reservoir capacitance to keep the DC ripple within required limits. Quite dangerous voltage levels when playing with these so care and knowledge required.

Not sure about Canadian power distribution. How do you guys get enough volts to power your 3 phase inverters?

Cheers

Bob

ps Note to self: Must add comment to the next edition of my motor write up to stress application to EU based power systems only.

are you saying you guys don't have 240V three phase power. only 240 single.
here in Canada we have 208.240'460 575 volt three phase. most shops here are 575v and transformers are used. before and after the vfd.you think 415 is hard to do try 575.not many making 575 units. cutting edge stuff . are you saying you are bridging the dc rectifiers to feed all three with single?if so how has that been working and is one hot line amp heavy.
does it get ride of the de-rating?


jack
 

9fingers

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Power out in the street is a 4 wire system, 415 v 3phase plus neutral which is bonded to earth at the local substation.

That means each phase is 240v to neutral and Neutral is a the odd volt or so above local earth with some arbitrary phase. Normally each house is wired to one phase plus neutral although for extra money you can have all four wires brought in.

So in UK most of us only have 240v to play with. In virtually all mainland Europe 3phase 415 is brought into the home as standard although you can opt not to have it -certainly in France.

I don't know what they have in Southern Ireland - maybe same as UK and Northern Ireland?

Bob
 
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