kinsella
Established Member
3 Phase to Single Phase : Startrite 275 conversion from 3 phase using Single phase input.
Colleagues
The following is my take on how I converted a 3 phase machine and it is meant to help others on the forum as I note it’s a common question on here for all sorts of 3 phase motors. (The assumption is you are either competent to undertake the work or you will seek professional advice, I take no responsibility, as it is your responsibility to follow proper procedures for your equipment or wellbeing, so if in doubt seek professional advice) Luckily there are loads of very experienced colleagues on here who will probably highlight were I could have taken alternative route or also to correct me if I actually get my facts wrong . But in my defence the following solution is either because of time, cost or ability. I used this forum and professional colleagues in my day to day job in construction management and colleagues in maintenance and electrical design engineers to bounce my assertions passed. Which helped me understand where I was wrong? Also, to be fair I think the general domestic DIY’er situations will be very similar to mine and this may give some pointers. I will add links where appropriate for further references.
I’ve recently received a Startrite 275 that was going to go in a skip. So as someone who has been on the lookout for a salvaged machine for a while. The timing was brilliant and the value was also good £0. The machine is 3 phase. As a weekend DIY’er, using direct 3 phases was not an option. So began the investigations on how to get the machine working. I found several treads on the forum which helped considerably.
These are linked below.
topic90119.html
topic20930.html
topic66355.html
topic77410.html
My options were as follows:
1. Sell the salvaged saw (I was not going to let a machine of this calibre go, as it was too good to even consider letting it go and the womble in me wanted to get it working
2. Buy a new single phase motor. This proved to be quite expensive as it meant replacing the motor, switching, pulley etc. So if it was just a motor replacement, it might have been cheap.
(Aug 2015 prices, quote extracts)
http://www.altsawsandspares.co.uk/spares.html
Part number Starcro 043 is the new replacement 240 volt 2HP foot mounted motor to suit, this has a 24mm diameter shaft, these are £236.00+vat.
If you need a 24mm bore pulley these are £61.20+vat
Part number KS0011 is the new 240 volt start/stop unit to suit the new motor, these are £85.00+vat
Carriage would be £15.00+vat, delivery 3-4 days from payment.
To be honest if money is not a problem, this is probably the easiest option. The company ALT Spares are excellent and this was where I was going to go until I realised I needed to buy a holiday for the family. So it was NO-Machine and a holiday. Or a slightly shorter holiday and a cheaper fix.
3. I also looked at using my existing Scheppach TKU table saw to see if I could salvage all the parts, i.e. the motor and switching. Unfortunately without doing a Heath Robinson this was a very awkward route as the motor mounting fixings were nowhere near the existing mounting points (didn’t match the Startrite), the arbour also looked like it wouldn't line up correctly. I gave up on this option very quickly as I figure I would butcher a perfectly working existing saw and a working solution wasn't guaranteed.
4. The next options are to keep the 3 Phase motor and use a converter or an inverter to run it.
A handy document on workshop motors can be found here, which explains the various motors in use. "Use of Induction Motors In The Home Workshop" by R C Minchin
http://homepage.ntlworld.com/bob.minchi ... Issue3.pdf
Having decided on keeping the 3 Phase Motor. The next options were as follows:
5. I got check prices for an inverter and a converter. A handy explanation is above in item 4 on the difference as I think these are commonly confused and intermixed assuming they are the same.
6. The first thing I had to do was take the cast iron top off the saw. I don’t have side access through the house, the workshop is at the back of the garden and the only option was to dismantle. Taking the top off is easy as it is held on with 8 bolts. The top is located onto the saw base with two locating pins. Once undone the top just lifts off. The top and bottom are both extremely heavy. But my wife (skivvy labourer) and I used moving skates and moved it through the house to the shed at the rear of the garden.
7. Once in the shed, I took the motor off to get easier access to it, to read the motor plate details. I opened up the wiring plate to see what alterations would be needed to the Delta/Star wirings. (it’s assumed by now you understand the difference between high/ low voltage ie Delta and Star, if not go back to item 4 and read the referenced document) Also when the inverter arrived it would be easier to test with it on a bench rather than in the body of the saw. See an example in the image below in a test state.
A YouTube video of the motor wiring etc can be viewed here:
https://youtu.be/SVq6MGBIltw
8. The motor on my saw was dual voltage, ie Delta and Star. See image. So my options were to either use a converter but I could also use an inverter. The option of using an inverter was to wire the motor to low voltage (Delta) and use an inverter to maintain the 3 phase low voltage supply. Ie you cannot convert 240v domestic supply to 415v without others boxes of tricks (not part of my research). So the only option for me was to use three phase on low voltage (ie domestic 240v supply size). You will need to check your motor. If you read the document link above in item 4 it will help you decipher if your motor is high voltage or dual voltage. If high, it just means your route to get your existing motor working is slightly different. Ie you’re back to items 2 or 3 using a converter.
9. Having watched a few videos on YouTube. Changing a motor from Star to Delta seemed to be quite easy, as all you have to do normally is move a few metal tabs and it normally tells you on the back of the wiring plate. Well, that was until I opened my motor wiring box. There were no connecting wiring links and it didn't look like any of the Star wirings on YouTube. But after a few internet searches I realised that it was OK, basically, the modern UVW outputs are also knows as ABC, XYZ and so on. Luckily I could see where ABC were on the high voltage wiring, the wiring details were clear on how to rewire the motor to low voltage.
10. I then focused on the inverter and I looked as several suppliers of inverters. The key item to note is that you will need a single phase input to a 3 phase output inverter. This is extremely important. If you salvage an inverter from somewhere you will need to check the input and outputs, otherwise you may need other bits of kit to get the inverter working. It should say on the unit detail plate.
11. My solutions were cost driven and were mainly to keep the pricing down to a minimum. Due to costs I opted for an inverter after having researched inverter manufactures and converters. The best pricing was an Invertek inverter. The ode 2 12150 1kb1x was the best option as it had an IP wall mount enclosure, it also had a dust proof and water proof rating. It’s a single to 3 phase unit. See link below. As of Aug 2015 it was circa £250 all in cost inc VAT and delivery. Some of the other costs for converters were in excess of this up to £600.
https://www.motorcontrolwarehouse.co.uk ... 1kb1x.html
A video of my investigations and connections can be viewed here: https://youtu.be/SVq6MGBIltw
12. A point to note is most of the existing switching on my Startrite was incompatible with the inverter. More importantly, the wiring of the inverter needs to go directly to the motor with no switching etc. between the inverter and the motor. i.e. no NVR switch, on/off or emergency off switches. These need to be done separately into the Control Terminal Panel (CTP) on the inverter. The manual explains this. You cannot just wire the old 3 phase wires into an inverter and all the old switching will work. If in doubt contact the inverter company and they tend to be very helpful. (Invertek were!!)
13. I managed to save the old emergency stop switch off the old saw and wire that into the CTP so I still kept the kick stop emergency brake on the existing saw configuration.
14. I bought 5m of 4-core cable from Screwfix. I also have a Startrite Mercury II drill press to tweak also, so I need more 4 core cable.
15. I then connected everything up roughly and tested the whole configuration before mounting it permanently into the saw, this was for ease as it was easier to do this at a bench and fine tune everything. A video of my investigations and connections can be viewed here: https://youtu.be/SVq6MGBIltw
16. I found a few YouTube videos on my Inverteck inverter as follows. These were extremely helpful in terms of wiring them up and adjusting the settings.
https://youtu.be/ROu2kd_Z-bk
https://youtu.be/HAL97NTx2v0
17. I connected all the incoming supplies as per manufacturer’s instructions. See video.
https://youtu.be/STta919XOWk
My investigations can be viewed here: https://youtu.be/SVq6MGBIltw
18. What did catch me out was, after adjusting the settings to make the motor run from the main panel and not a separate control switch; I also adjusted the volt rating of the inverter to match the 3 phase motor to protect the motor, mine states 5.2 Volts. After setting all the settings. I then pressed the green start button to start the motor and…… #-o #-o ……nothing happened. I turned it off and rechecked all the wiring connections…………… restarted again and……… #-o #-o ………. nothing…………….. I did it a few time as we all know when it doesn't work first time, do it again and again until caveman brain works out it’s not working……………………….. I scratched my head, I scratched my bal………… nothing. I then checked the error log on the inverter and nothing………… :? :? ………… At this point I stood there thinking I've done everything right and it isn't working and was wondering if the motor had had it as I had not witnessed that it had ever worked. I was contemplating following a process of elimination to test circuits of the motor which was easily hours and hours of work that I'm not even competent to do. I thought no way, I then relooked at the settings and suddenly it dawned on me. The motor speed is set from the panel and the default is zero and I thought that doesn't look right. I think the default in the setting assumes a rotary connector to adjust the speed of the motor and thus its default out of the box is zero. I pressed the up arrow and nothing happened, or should I say nothing perceivable happened. As the speed ramps up in 0.0 increments. i.e. by 0.9% the motor is probably moving but you’d never pick it up visually. I ramped it up and by 10% I noticed it was moving. Then at 50% if was giving it welly!. I realised it was just a setting and everything was ok with the world. And saved me a tonne of abortive work. The great thing with this inverter is it remembers the last setting. So when I stopped and restarted it, it immediately went back to the 50% that I previously set. i.e. when I'm up and running and I set it to 100%, it will always be 100% when I restart unless I adjust it manually. As it’s a table saw and not a drill or lathe. I will never alter the variable speed that I can see at present. Mind you I have two sizes of blades to put in the machine and so it may need adjusting.
19. Having proved everything works, I moved to final install and permanent mounting.
20. I then mounted the inverter onto the table saw. The inverter is quite bulky but the overhand on the Startrite is considerable so I opted to mount directly to the base unit and use a single phase cable with a standard plug. I also connected the old emergency stop switch to ports 1 and 2 on the CTP. I wired the incoming single phase supply as per manufacturer’s instructions and then the 3 phase outputs. Connecting all earth cables as appropriate, used rubber grommets so there is no metal to cabling scenarios without rubber seals or grommets. Hey presto. I'm now operational.
21. Cost of Startrite £0 as its salvaged. Cost of inverter £250, plus 4 core cable £10 another few £’s for grommets. Due to its size and my limited space, i welded up a wheel base and bought some heavy duty castors from Screwfix for another £10. So from non-usable 3 phase saw to usable 3 phase saw equated to £280.
Summary:
A point to note, while I don't mention the earthing of cables, the Inverter is earthed and the 4 core cable is earthed to the motor housing (you can see the green/yellow cable under the UVW wiring in the video) so the whole set up if fully earthed and tested before I moved from any of the wiring stages to ensure that there wasn't an existing fault with the motor.
Hopefully those of you who find yourself in a similar position may find this post useful. I am no electrician and only know basic knowledge but from research on this forum and the PDF guide on motors I managed to go from zero knowledge on motors to turning a 3 phase saw that was unusable to me to a working 3 phase saw. Feel free to post questions, i may not be able to answer them but the colleagues on here have been extremely good in jumping in and posting clarifications.
Colleagues
The following is my take on how I converted a 3 phase machine and it is meant to help others on the forum as I note it’s a common question on here for all sorts of 3 phase motors. (The assumption is you are either competent to undertake the work or you will seek professional advice, I take no responsibility, as it is your responsibility to follow proper procedures for your equipment or wellbeing, so if in doubt seek professional advice) Luckily there are loads of very experienced colleagues on here who will probably highlight were I could have taken alternative route or also to correct me if I actually get my facts wrong . But in my defence the following solution is either because of time, cost or ability. I used this forum and professional colleagues in my day to day job in construction management and colleagues in maintenance and electrical design engineers to bounce my assertions passed. Which helped me understand where I was wrong? Also, to be fair I think the general domestic DIY’er situations will be very similar to mine and this may give some pointers. I will add links where appropriate for further references.
I’ve recently received a Startrite 275 that was going to go in a skip. So as someone who has been on the lookout for a salvaged machine for a while. The timing was brilliant and the value was also good £0. The machine is 3 phase. As a weekend DIY’er, using direct 3 phases was not an option. So began the investigations on how to get the machine working. I found several treads on the forum which helped considerably.
These are linked below.
topic90119.html
topic20930.html
topic66355.html
topic77410.html
My options were as follows:
1. Sell the salvaged saw (I was not going to let a machine of this calibre go, as it was too good to even consider letting it go and the womble in me wanted to get it working
2. Buy a new single phase motor. This proved to be quite expensive as it meant replacing the motor, switching, pulley etc. So if it was just a motor replacement, it might have been cheap.
(Aug 2015 prices, quote extracts)
http://www.altsawsandspares.co.uk/spares.html
Part number Starcro 043 is the new replacement 240 volt 2HP foot mounted motor to suit, this has a 24mm diameter shaft, these are £236.00+vat.
If you need a 24mm bore pulley these are £61.20+vat
Part number KS0011 is the new 240 volt start/stop unit to suit the new motor, these are £85.00+vat
Carriage would be £15.00+vat, delivery 3-4 days from payment.
To be honest if money is not a problem, this is probably the easiest option. The company ALT Spares are excellent and this was where I was going to go until I realised I needed to buy a holiday for the family. So it was NO-Machine and a holiday. Or a slightly shorter holiday and a cheaper fix.
3. I also looked at using my existing Scheppach TKU table saw to see if I could salvage all the parts, i.e. the motor and switching. Unfortunately without doing a Heath Robinson this was a very awkward route as the motor mounting fixings were nowhere near the existing mounting points (didn’t match the Startrite), the arbour also looked like it wouldn't line up correctly. I gave up on this option very quickly as I figure I would butcher a perfectly working existing saw and a working solution wasn't guaranteed.
4. The next options are to keep the 3 Phase motor and use a converter or an inverter to run it.
A handy document on workshop motors can be found here, which explains the various motors in use. "Use of Induction Motors In The Home Workshop" by R C Minchin
http://homepage.ntlworld.com/bob.minchi ... Issue3.pdf
Having decided on keeping the 3 Phase Motor. The next options were as follows:
5. I got check prices for an inverter and a converter. A handy explanation is above in item 4 on the difference as I think these are commonly confused and intermixed assuming they are the same.
6. The first thing I had to do was take the cast iron top off the saw. I don’t have side access through the house, the workshop is at the back of the garden and the only option was to dismantle. Taking the top off is easy as it is held on with 8 bolts. The top is located onto the saw base with two locating pins. Once undone the top just lifts off. The top and bottom are both extremely heavy. But my wife (skivvy labourer) and I used moving skates and moved it through the house to the shed at the rear of the garden.
7. Once in the shed, I took the motor off to get easier access to it, to read the motor plate details. I opened up the wiring plate to see what alterations would be needed to the Delta/Star wirings. (it’s assumed by now you understand the difference between high/ low voltage ie Delta and Star, if not go back to item 4 and read the referenced document) Also when the inverter arrived it would be easier to test with it on a bench rather than in the body of the saw. See an example in the image below in a test state.
A YouTube video of the motor wiring etc can be viewed here:
https://youtu.be/SVq6MGBIltw
8. The motor on my saw was dual voltage, ie Delta and Star. See image. So my options were to either use a converter but I could also use an inverter. The option of using an inverter was to wire the motor to low voltage (Delta) and use an inverter to maintain the 3 phase low voltage supply. Ie you cannot convert 240v domestic supply to 415v without others boxes of tricks (not part of my research). So the only option for me was to use three phase on low voltage (ie domestic 240v supply size). You will need to check your motor. If you read the document link above in item 4 it will help you decipher if your motor is high voltage or dual voltage. If high, it just means your route to get your existing motor working is slightly different. Ie you’re back to items 2 or 3 using a converter.
9. Having watched a few videos on YouTube. Changing a motor from Star to Delta seemed to be quite easy, as all you have to do normally is move a few metal tabs and it normally tells you on the back of the wiring plate. Well, that was until I opened my motor wiring box. There were no connecting wiring links and it didn't look like any of the Star wirings on YouTube. But after a few internet searches I realised that it was OK, basically, the modern UVW outputs are also knows as ABC, XYZ and so on. Luckily I could see where ABC were on the high voltage wiring, the wiring details were clear on how to rewire the motor to low voltage.
10. I then focused on the inverter and I looked as several suppliers of inverters. The key item to note is that you will need a single phase input to a 3 phase output inverter. This is extremely important. If you salvage an inverter from somewhere you will need to check the input and outputs, otherwise you may need other bits of kit to get the inverter working. It should say on the unit detail plate.
11. My solutions were cost driven and were mainly to keep the pricing down to a minimum. Due to costs I opted for an inverter after having researched inverter manufactures and converters. The best pricing was an Invertek inverter. The ode 2 12150 1kb1x was the best option as it had an IP wall mount enclosure, it also had a dust proof and water proof rating. It’s a single to 3 phase unit. See link below. As of Aug 2015 it was circa £250 all in cost inc VAT and delivery. Some of the other costs for converters were in excess of this up to £600.
https://www.motorcontrolwarehouse.co.uk ... 1kb1x.html
A video of my investigations and connections can be viewed here: https://youtu.be/SVq6MGBIltw
12. A point to note is most of the existing switching on my Startrite was incompatible with the inverter. More importantly, the wiring of the inverter needs to go directly to the motor with no switching etc. between the inverter and the motor. i.e. no NVR switch, on/off or emergency off switches. These need to be done separately into the Control Terminal Panel (CTP) on the inverter. The manual explains this. You cannot just wire the old 3 phase wires into an inverter and all the old switching will work. If in doubt contact the inverter company and they tend to be very helpful. (Invertek were!!)
13. I managed to save the old emergency stop switch off the old saw and wire that into the CTP so I still kept the kick stop emergency brake on the existing saw configuration.
14. I bought 5m of 4-core cable from Screwfix. I also have a Startrite Mercury II drill press to tweak also, so I need more 4 core cable.
15. I then connected everything up roughly and tested the whole configuration before mounting it permanently into the saw, this was for ease as it was easier to do this at a bench and fine tune everything. A video of my investigations and connections can be viewed here: https://youtu.be/SVq6MGBIltw
16. I found a few YouTube videos on my Inverteck inverter as follows. These were extremely helpful in terms of wiring them up and adjusting the settings.
https://youtu.be/ROu2kd_Z-bk
https://youtu.be/HAL97NTx2v0
17. I connected all the incoming supplies as per manufacturer’s instructions. See video.
https://youtu.be/STta919XOWk
My investigations can be viewed here: https://youtu.be/SVq6MGBIltw
18. What did catch me out was, after adjusting the settings to make the motor run from the main panel and not a separate control switch; I also adjusted the volt rating of the inverter to match the 3 phase motor to protect the motor, mine states 5.2 Volts. After setting all the settings. I then pressed the green start button to start the motor and…… #-o #-o ……nothing happened. I turned it off and rechecked all the wiring connections…………… restarted again and……… #-o #-o ………. nothing…………….. I did it a few time as we all know when it doesn't work first time, do it again and again until caveman brain works out it’s not working……………………….. I scratched my head, I scratched my bal………… nothing. I then checked the error log on the inverter and nothing………… :? :? ………… At this point I stood there thinking I've done everything right and it isn't working and was wondering if the motor had had it as I had not witnessed that it had ever worked. I was contemplating following a process of elimination to test circuits of the motor which was easily hours and hours of work that I'm not even competent to do. I thought no way, I then relooked at the settings and suddenly it dawned on me. The motor speed is set from the panel and the default is zero and I thought that doesn't look right. I think the default in the setting assumes a rotary connector to adjust the speed of the motor and thus its default out of the box is zero. I pressed the up arrow and nothing happened, or should I say nothing perceivable happened. As the speed ramps up in 0.0 increments. i.e. by 0.9% the motor is probably moving but you’d never pick it up visually. I ramped it up and by 10% I noticed it was moving. Then at 50% if was giving it welly!. I realised it was just a setting and everything was ok with the world. And saved me a tonne of abortive work. The great thing with this inverter is it remembers the last setting. So when I stopped and restarted it, it immediately went back to the 50% that I previously set. i.e. when I'm up and running and I set it to 100%, it will always be 100% when I restart unless I adjust it manually. As it’s a table saw and not a drill or lathe. I will never alter the variable speed that I can see at present. Mind you I have two sizes of blades to put in the machine and so it may need adjusting.
19. Having proved everything works, I moved to final install and permanent mounting.
20. I then mounted the inverter onto the table saw. The inverter is quite bulky but the overhand on the Startrite is considerable so I opted to mount directly to the base unit and use a single phase cable with a standard plug. I also connected the old emergency stop switch to ports 1 and 2 on the CTP. I wired the incoming single phase supply as per manufacturer’s instructions and then the 3 phase outputs. Connecting all earth cables as appropriate, used rubber grommets so there is no metal to cabling scenarios without rubber seals or grommets. Hey presto. I'm now operational.
21. Cost of Startrite £0 as its salvaged. Cost of inverter £250, plus 4 core cable £10 another few £’s for grommets. Due to its size and my limited space, i welded up a wheel base and bought some heavy duty castors from Screwfix for another £10. So from non-usable 3 phase saw to usable 3 phase saw equated to £280.
Summary:
A point to note, while I don't mention the earthing of cables, the Inverter is earthed and the 4 core cable is earthed to the motor housing (you can see the green/yellow cable under the UVW wiring in the video) so the whole set up if fully earthed and tested before I moved from any of the wiring stages to ensure that there wasn't an existing fault with the motor.
Hopefully those of you who find yourself in a similar position may find this post useful. I am no electrician and only know basic knowledge but from research on this forum and the PDF guide on motors I managed to go from zero knowledge on motors to turning a 3 phase saw that was unusable to me to a working 3 phase saw. Feel free to post questions, i may not be able to answer them but the colleagues on here have been extremely good in jumping in and posting clarifications.
