I use a VFD (220v) to run/control my disk grinder. It rocks. These little guys aren't cheap. I have another motor that I'd like make into a second disk grinder using the same VFD. Can I use some kind of manual switch between the motors and the vfd to switch back and forth between the motors? What kind of switch is that going to be? type slow, this electrical stuff is mostly beyond me...
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VFD wiring switch question please
- Thread starter tmickley
- Start date
Here is a link to an ebay auction for a VFD 2hp, 1/3phase 220v in, 3phase out. This is just the deal to run your grinder on a 2hp AC motor. I just bought an identical one like this one from this same seller for $120. This is about half of what they normally go for, especially for a 2hp.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7533206932&category=42895&ssPageName=WDVW&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7533206932&category=42895&ssPageName=WDVW&rd=1
Tracy,
Just checked the specs listed on EBAY for that VFD. The sellers spec list calls for 3 phase input. If this is true, then this won't work on single phase input.
Also tried to find the manual on the makers web site and could not find it. Many (essentially all) VFD's are nearly impossible to program and run with the owners manual.
I think this one would be a good one to pass on.
Just my .02
Mike
Just checked the specs listed on EBAY for that VFD. The sellers spec list calls for 3 phase input. If this is true, then this won't work on single phase input.
Also tried to find the manual on the makers web site and could not find it. Many (essentially all) VFD's are nearly impossible to program and run with the owners manual.
I think this one would be a good one to pass on.
Just my .02
Mike
Tracy
If you connect both motors directly to the output of the VFD, they will both run at the same time, at similar speeds, assuming two motors with similar specifications (hp, nominal speed). They will probably not run at the same speed since you will be connecting them to different loads. The two 2hp motors could draw up to 4hp of energy from the VFD, so a 2hp VFD would likely trip out under any significant load. Also, it would probably be rather dangerous to have both machines running at the same time.
I suspect that you only want one machine running at a time. To do this you will need a three-pole change-over type switch. These can be quite expensive and you would have to go to an electrical wholesaler (who is willing to sell at retail) to purchase one. It might be not much more to buy a second Delta VFD! It would probably be much cheaper to buy two three-phase circuit breakers (you may even be able to get them from Home Depot) and mount them adjacent to each other in a suitably sized electrical box. Appendix B of the manual gives you the required rating (30 Amp). You would then close only the breaker for the motor that you want to run before starting. If you are mechanically inclined, you could work out some sort of interlock mechanism so that only one of the two breakers can be closed at any time and allow the one that is on to trip in the event of a fault. Large UPS systems, like those that manufactured at Toshiba, use a scheme like this since there are no hand operated change-over switches rated for 200 to 300 Amps. Let me know if you do want to get a three-pole change-over type switch, I will ask our supplier for recommendations on Monday.
The Delta VFD that you bought is probably pretty good. I have no direct experience with them but I do know that the parent company, Delta, manufactures quite a wide range of industrial equipment of good quality (maybe not the absolute best) at reasonable prices. The lower end products from a lot of major brands of industrial electrical equipment are really Delta products relabeled, perhaps with some cosmetic changes. My last job was at a manufacturer of VFD's and my boss there had visited Delta to investigate setting up such a deal. He saw VFD's coming off the assembly line with some pretty prominent names on them. I think that Siemens of Germany was one of them.
I may be wrong, but it looks like you may not get 2hp output power since the VFD015S23B may really only be meant to be used with three-phase inputs and might not be able to put out 2hp when connected to a single-phase input. A call to their sales office in North Carolina would clarify this. It will be hard to measure the output power you are getting unless you have the equipment to measure the current and the voltage and their relative phase relationship. I guess the real test is if the VFD trips out when you put the heaviest load on your machine. If the VFD015S23B is doing the job for you, then it was a great buy at $120. Heck, I would buy one if I hadn't picked up a bunch of refurbished engineering prototypes after a lab clean up at my last job.
Phil
If you connect both motors directly to the output of the VFD, they will both run at the same time, at similar speeds, assuming two motors with similar specifications (hp, nominal speed). They will probably not run at the same speed since you will be connecting them to different loads. The two 2hp motors could draw up to 4hp of energy from the VFD, so a 2hp VFD would likely trip out under any significant load. Also, it would probably be rather dangerous to have both machines running at the same time.
I suspect that you only want one machine running at a time. To do this you will need a three-pole change-over type switch. These can be quite expensive and you would have to go to an electrical wholesaler (who is willing to sell at retail) to purchase one. It might be not much more to buy a second Delta VFD! It would probably be much cheaper to buy two three-phase circuit breakers (you may even be able to get them from Home Depot) and mount them adjacent to each other in a suitably sized electrical box. Appendix B of the manual gives you the required rating (30 Amp). You would then close only the breaker for the motor that you want to run before starting. If you are mechanically inclined, you could work out some sort of interlock mechanism so that only one of the two breakers can be closed at any time and allow the one that is on to trip in the event of a fault. Large UPS systems, like those that manufactured at Toshiba, use a scheme like this since there are no hand operated change-over switches rated for 200 to 300 Amps. Let me know if you do want to get a three-pole change-over type switch, I will ask our supplier for recommendations on Monday.
The Delta VFD that you bought is probably pretty good. I have no direct experience with them but I do know that the parent company, Delta, manufactures quite a wide range of industrial equipment of good quality (maybe not the absolute best) at reasonable prices. The lower end products from a lot of major brands of industrial electrical equipment are really Delta products relabeled, perhaps with some cosmetic changes. My last job was at a manufacturer of VFD's and my boss there had visited Delta to investigate setting up such a deal. He saw VFD's coming off the assembly line with some pretty prominent names on them. I think that Siemens of Germany was one of them.
I may be wrong, but it looks like you may not get 2hp output power since the VFD015S23B may really only be meant to be used with three-phase inputs and might not be able to put out 2hp when connected to a single-phase input. A call to their sales office in North Carolina would clarify this. It will be hard to measure the output power you are getting unless you have the equipment to measure the current and the voltage and their relative phase relationship. I guess the real test is if the VFD trips out when you put the heaviest load on your machine. If the VFD015S23B is doing the job for you, then it was a great buy at $120. Heck, I would buy one if I hadn't picked up a bunch of refurbished engineering prototypes after a lab clean up at my last job.
Phil
- Joined
- Jun 8, 2000
- Messages
- 3,140
Tracy,
Phil certainly knows more about VFD's than I ever will. Hey Phil, think Tosh has any more NOS stuff they want to get rid of?
By my understanding, a VFD rated for three phase input can be run on single phase input most of the time, but must be derated to 1/2 it's rated output power.
You might look over at www.practicalmachinist.com as they have a whole forum devoted to VFDs and RPCs. There's also a for sale section and one of the guys there usually has pretty good deals on VFDs in the range you're looking for. HAving a seperate one for each machine would be beneficial as you can tehn tailor things like ramp time to the machine's specific needs.
Phil certainly knows more about VFD's than I ever will. Hey Phil, think Tosh has any more NOS stuff they want to get rid of?
By my understanding, a VFD rated for three phase input can be run on single phase input most of the time, but must be derated to 1/2 it's rated output power.
You might look over at www.practicalmachinist.com as they have a whole forum devoted to VFDs and RPCs. There's also a for sale section and one of the guys there usually has pretty good deals on VFDs in the range you're looking for. HAving a seperate one for each machine would be beneficial as you can tehn tailor things like ramp time to the machine's specific needs.
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- Oct 29, 2003
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If a person isn't looking to spend much money just put a 4 prong plug on each motor and an outlet on the VFD then just plug in the one you are using.
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- Sep 21, 2001
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What Pete said. I bought high quality Hubbell plugs fairly cheap on Ebay. Be very careful that the males and female plugs are three phase and that they MATCH!
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- Jun 25, 2001
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Tracy
I use a 2 hp rated VFD
connected to both my Enco V nee mill and surface my grinder.
I'm also building a 3 phase disk grinder that will be hooked up to it as well
all are hard wired with no plugs. just turn them on and go..
I just use one machine at a time so I don't go over the VFD rating of 2hp..
I use a 2 hp rated VFD
connected to both my Enco V nee mill and surface my grinder.
I'm also building a 3 phase disk grinder that will be hooked up to it as well
all are hard wired with no plugs. just turn them on and go..
I just use one machine at a time so I don't go over the VFD rating of 2hp..
Hi Mike, This VFD will run 1 phase. I've had this exact model before and it works fine. It is documented in the manual that it will run 1 phase, just not very well. I had 2 electricians and one motor shop tell it couldn't be done and then I found it documented by one or two sentences in the manual. Not being able to measure it, I'm guessing since it only runs 1 phase instead of three, it probably should be derated a bit. The potentiometer doesn't work to control the speed, you have to do that by pressing the membrane keypads. If the one currently listed doesn't go too much above what I paid for the first one, I'll buy it as a spare.micad said:
Phil, I knew there would be a specific switch, I just didn't know the name. I also figured they would be expensive but not that much. If you get a chance and not have to go out of your way, could you ask if your work has one to sell? I'll never find one locally so I guess I'll need to start looking around the net for some kind of switch box I can cobble together that interlocks so only one can run at a time. Thanks for your help.
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- Jun 25, 2001
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- 8,474
Tracytmickley said:
yes one will be open..
both machines have their own factory switch
I wired direct to both machines (direct into their own factory switch) from the one VFD .
the only other switch, is the breaker that runs the 220 input to the VFD
I like those 3 Phase motors (Cheap)
Dan, I think your way is probably going to be easiest to scrounge up here. I'll probably end up going to Home Depot and pick up a couple triple pole switches (I don't think I'll need to switch the ground) and some switch boxes and rig up a set of switches to the one VFD. I like those AC 3 phase motors myself, I can't believe you cheap you can get them. Thanks.
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- Jun 25, 2001
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- 8,474
tmickley said:
my miller had a reverse switch anyway and the surface grinder
need not to be reversed . once I get my disk grinder going I'll have to
rig it up with a switch to reverse that.
if you would let me know,
I'd like to know what you end up getting for a switch for yours?
I believe the only wires you have to switch/swap, for reverse is two of the 3 pos legs on the 3 ph motor it self. and it don't matter which ones..just two of them..
the ground is to the motor frame right?
I'm thinking a 3 position 3 pole switch with center off.?
don't quote me though
it's been a while since I've messed with this stuff...
This last 1 hp motor I got was $89.00 new and it wasn't from a discount outfit either..
Pete's idea of using plugs and sockets is another inexpensive way to go. I would suggest connecting the socket (female) to the VFD and the plug (male). If you happen to turn on the VFD with no motor connected, no live pins would be exposed to potentially electrocute you. How much are you able to buy these plugs and sockets for? Are special tools needed, ie. special crimpers?
Using the plug and socket system would allow you to mount the VFD permanently to the wall and move your equipment around as needed.
Dan's system of switches for each motor is functionally the same as my suggestion of using breakers since the breakers can be used as switches. Double-pole switches would only take care of two of the three-phases. You will need three-phase switches or breakers since you want to connect or disconnect all three phases at the same time.
For a switch box, use the plastic boxes that they use for surface mount installations outdoors. Just pick one big enough to hold your switch(es). If the switches or breakers are too big, use two.
One of our suppliers sells us so much electrical parts that they put a salesman in our facility to take care of us. I will ask him for a recommendation for a three-phase change-over switch and get an approximate price. I don't think that the company he works for has operations in Minnesota though.
I took a closer look at the manual for the Delta VFD. I am impressed with it's sophistication and flexibility. You will have to read through the programming section of the manual to get the most from it though. It should be possible to use the potentiometer on the front of your Delta VFD to control the speed of the motor by setting parameter 2-00 (see page 5-12). It should also be possible to use an externally connected potentiometer to control the motor speed by setting this parameter to the appropriate value. The default is for the speed to be controlled by the keypad, as you have now. If you wish, you can even connect to a network and control the speed over the internet by setting this parameter to another value. It should also be possible to control the direction of rotation forward and reverse) of your motor using either the keypad buttons or external switches by setting some other parameters. The VFD output would do the "swapping of connections" that Dan described by changing how it produces the three output phases. You should not need any external reversing switches at all.
Most VFD's have three-phase inputs since most users of VFD's have three-phase power available. The input rectifiers would be sized appropriately for the required three-phase currents. Connecting to a single-phase supply, one hase to keep within the same current limits. This leads to the input power being about 57% of what it would be if connected to a three-phase supply. This is why the output power of most VFD's must be derated to about half when connected to a single-phase supply. On some models, input rectifiers with higher current ratings are installed so that the output power does not have to be derated. Of course, the larger rectifiers cost more so the resulting VFD also costs more. The model that John bought from Toshiba is one of the few made that have the larger rectifiers. I can ask on Monday if they still have stock of those.
Using the plug and socket system would allow you to mount the VFD permanently to the wall and move your equipment around as needed.
Dan's system of switches for each motor is functionally the same as my suggestion of using breakers since the breakers can be used as switches. Double-pole switches would only take care of two of the three-phases. You will need three-phase switches or breakers since you want to connect or disconnect all three phases at the same time.
For a switch box, use the plastic boxes that they use for surface mount installations outdoors. Just pick one big enough to hold your switch(es). If the switches or breakers are too big, use two.
One of our suppliers sells us so much electrical parts that they put a salesman in our facility to take care of us. I will ask him for a recommendation for a three-phase change-over switch and get an approximate price. I don't think that the company he works for has operations in Minnesota though.
I took a closer look at the manual for the Delta VFD. I am impressed with it's sophistication and flexibility. You will have to read through the programming section of the manual to get the most from it though. It should be possible to use the potentiometer on the front of your Delta VFD to control the speed of the motor by setting parameter 2-00 (see page 5-12). It should also be possible to use an externally connected potentiometer to control the motor speed by setting this parameter to the appropriate value. The default is for the speed to be controlled by the keypad, as you have now. If you wish, you can even connect to a network and control the speed over the internet by setting this parameter to another value. It should also be possible to control the direction of rotation forward and reverse) of your motor using either the keypad buttons or external switches by setting some other parameters. The VFD output would do the "swapping of connections" that Dan described by changing how it produces the three output phases. You should not need any external reversing switches at all.
Most VFD's have three-phase inputs since most users of VFD's have three-phase power available. The input rectifiers would be sized appropriately for the required three-phase currents. Connecting to a single-phase supply, one hase to keep within the same current limits. This leads to the input power being about 57% of what it would be if connected to a three-phase supply. This is why the output power of most VFD's must be derated to about half when connected to a single-phase supply. On some models, input rectifiers with higher current ratings are installed so that the output power does not have to be derated. Of course, the larger rectifiers cost more so the resulting VFD also costs more. The model that John bought from Toshiba is one of the few made that have the larger rectifiers. I can ask on Monday if they still have stock of those.
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- Jun 8, 2000
- Messages
- 3,140
pso said:
As mentioned before, Phil is THE MAN when it comes to VFDs.
For reference purposes, the units I got were VFS7S-2015UP. These have the heavier rectifiers that he mentions that are specified tor single phase 220 input and will generate 7.5 amps of variable frequency three phase output (enough for a true 2hp rating).
Phil, thanks for the assistance. I meant to type 3 pole and typed 2 pole.
I've purchased several 220v 20 to 30 plugs and sockets lately (to hook up welders) to know they are stupidly expensive. The cheapest I found at Home Depot is $18 for plug. The socket is a little cheaper but not much.
I am inherently lazy and value efficiency of work shop above everything, including my money and will need to be able to just flip a switch to turn it on. I've been looking on the net and I always thought you could find anything you wanted but a 3 pole change over switch has been a tough find. In the UK, they are lousy with the things but North America doesn't use them as much apparantly.
The derating makes sense using only 1 leg input. Since this is for a disk grinder, the load will be light enough that I won't be pulling enough amps to be a problem in this application but now I'll need to start looking for a true 2hp output using a 1 phase input. Any ideas on what to look for there? Could it be as simple (loosely, I understand) as looking for a 6hp VFD?
Again, any help finding a useable switch is much appreciated.
I've purchased several 220v 20 to 30 plugs and sockets lately (to hook up welders) to know they are stupidly expensive. The cheapest I found at Home Depot is $18 for plug. The socket is a little cheaper but not much.
I am inherently lazy and value efficiency of work shop above everything, including my money and will need to be able to just flip a switch to turn it on. I've been looking on the net and I always thought you could find anything you wanted but a 3 pole change over switch has been a tough find. In the UK, they are lousy with the things but North America doesn't use them as much apparantly.
The derating makes sense using only 1 leg input. Since this is for a disk grinder, the load will be light enough that I won't be pulling enough amps to be a problem in this application but now I'll need to start looking for a true 2hp output using a 1 phase input. Any ideas on what to look for there? Could it be as simple (loosely, I understand) as looking for a 6hp VFD?
Again, any help finding a useable switch is much appreciated.
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- Jun 25, 2001
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- 8,474
Mine is a FVR-C9S made by Fuji
6.4 amp at 3 phase 0-100 Hz rated for two full HP from 220 input.
thinking about you wanting a 6hp rated unit..
you may know this anyway but the higher the hp rating you go the higher the price (by a lot) for these babies ..
when I bought mine it was just over $300.00 if I recall.
you just have to think about how much HP you'll be using at one time?
I think for me I'd go with two 2 hp units instead of one 6hp jobbie, because, I'm not going to run more than
2 motors 3 ph at a time anyway. and I'd have the
two just in case I blow one up as a back up if needed..
remember the shop-smith 5 or what ever tools in one??
It's like, if your one motor runs your whole shop and it bites the dust nothing now works, the whole shop is down..
I might mention the switch you get, does not have to be very heavy, where
the amp rating is low on each leg of the 3 ph..for safety I would set up a switch on each motor regardless of plugs and such right were you can get at it easily. hard wiring keep wiring out of the way too. just 2 cents for some common since
to recap on my breaker,, the only breaker I use, is on the 220 end right out of my sub panel that way you are sure there is no power to anything it supplies if shut off,
if I'm not using the motors the VFD does not have to be on anyway so I just trip the braker.
6.4 amp at 3 phase 0-100 Hz rated for two full HP from 220 input.
thinking about you wanting a 6hp rated unit..
you may know this anyway but the higher the hp rating you go the higher the price (by a lot) for these babies
..when I bought mine it was just over $300.00 if I recall.
you just have to think about how much HP you'll be using at one time?
I think for me I'd go with two 2 hp units instead of one 6hp jobbie, because, I'm not going to run more than
2 motors 3 ph at a time anyway. and I'd have the
two just in case I blow one up as a back up if needed..
remember the shop-smith 5 or what ever tools in one??
It's like, if your one motor runs your whole shop and it bites the dust nothing now works, the whole shop is down..
I might mention the switch you get, does not have to be very heavy, where
the amp rating is low on each leg of the 3 ph..for safety I would set up a switch on each motor regardless of plugs and such right were you can get at it easily. hard wiring keep wiring out of the way too. just 2 cents for some common since
to recap on my breaker,, the only breaker I use, is on the 220 end right out of my sub panel that way you are sure there is no power to anything it supplies if shut off,
if I'm not using the motors the VFD does not have to be on anyway so I just trip the braker.
Tracy
If you feel that you really need 2 hp out of your VFD, then get one of the VFS7S-2015UP from Toshiba. It is an obsolete model so it does not appear in any of the price guides that they give out to their distributors. The stock that they have is new and they would love to get rid of it. Ask for Shane Cresta in the ASD Marketing Department at 800 231 1412 or 713 466 0277. I do not work in that department nor do I get any sort of commission.
I had looked at the various VFD's offered by a large number of manufacturers about a year ago and found that very few offer a model with the larger input rectifiers so that no derating is required when running from single-phase supplies. It is possible to use a VFD with double rating but you would have to pay much more than getting one with bigger input rectifiers.
For a breaker to connect each motor to your VFD, gangl together three single-pole 10 to 15 Amp 230 V breakers or look for something like this
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7532635474&category=104232&ssPageName=WDVW&rd=1
or
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2569765136&category=104232&ssPageName=WD1V&rd=1
I will look up how much the plugs and sockets that we use at work are tomorrow.
Phil
If you feel that you really need 2 hp out of your VFD, then get one of the VFS7S-2015UP from Toshiba. It is an obsolete model so it does not appear in any of the price guides that they give out to their distributors. The stock that they have is new and they would love to get rid of it. Ask for Shane Cresta in the ASD Marketing Department at 800 231 1412 or 713 466 0277. I do not work in that department nor do I get any sort of commission.
I had looked at the various VFD's offered by a large number of manufacturers about a year ago and found that very few offer a model with the larger input rectifiers so that no derating is required when running from single-phase supplies. It is possible to use a VFD with double rating but you would have to pay much more than getting one with bigger input rectifiers.
For a breaker to connect each motor to your VFD, gangl together three single-pole 10 to 15 Amp 230 V breakers or look for something like this
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7532635474&category=104232&ssPageName=WDVW&rd=1
or
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2569765136&category=104232&ssPageName=WD1V&rd=1
I will look up how much the plugs and sockets that we use at work are tomorrow.
Phil
Phil, thanks for all the help. I expect one of these days for my Baldor 1.5hp DC motor to bite the dust. I have a 2hp AC motor and was looking for a VFD on the cheap that would drive it when I stumbled onto that other one I will use for a horizontal disk grinder. I have stumbled onto a 3-pole double throw switch on eBay that I am going to buy and it will be perfect for running two motors (not at the same time) off of one VFD.