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IndustryArena Forum > CNC Electronics > Phase Converters > Mitsubishi Freqrol FR-SF on Single Phase?
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  1. #1

    Mitsubishi Freqrol FR-SF on Single Phase?

    Has anyone overridden the input phase detection on a Mitsubishi Freqrol FR-SF drive to run it from single phase input rather than 3 phase?

    I have connected 2 of the small wires (red and blue) that go to the control side of the drive to the same phase on the input connector, and the other (white) to the other phase (looking at the schematic in the service manual to see which of the 2 it made sense to connect together)

    With the main breaker off (that feeds the rectifiers / dc bus), if I power up the control side, I get only alarm 24 sometimes (main breaker trip - it's intentionally open), and sometimes alarm 24 and 26 (26 is input phase loss detected). If the main breaker is on, I get alarm 26 every time no matter what. I don't understand why sometimes with the main breaker off, alarm 26 goes away.

    Is there a trick to disabling the phase detection? Can I just use an RC delay circuit to simulate 3 phase (with 2 stages of 120 degree phase delay) to the phase detection pins on the control board? I know the 3 phase for detection goes to CON 102 pins 7 8 and 9 on the SF-CA board, and it appears that it goes through a resistive divider before it goes to the ADC, but I haven't fully traced out the circuit yet. Clearly it seems to be doing something more intelligent than just checking if there's voltage between R-S S-T and R-T. I tried re-ordering the phase detection pins to the control board in every combination that made sense, and I get the phase error no matter what.

    I see there's a jumper on the board to disable the main breaker open alarm to test the inverter/converter waveforms, but no jumper to disable phase detection, and no parameter (unless it's one of the parameters listed in the manual as "do not use - set to 0")

    I already know about "it's not a good idea", and "derate the vfd vs the motor" etc etc (it's already a 22KW drive running an 11KW motor)

  2. #2
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    AFAIK you cannot run that version/model on 1ph you will get alarm 26 if any phase is missing.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  3. #3

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by Al_The_Man View Post
    AFAIK you cannot run that version/model on 1ph you will get alarm 26 if any phase is missing.
    Al.
    "Cannot" sounds like a challenge to me...

    Traced out the circuit, and simulated - looks like just some digital pulses and perhaps the analog input to the ADC needs to be emulated... wonder how smart it is with the peaks in the analog signal corresponding to the digital pulses...
    Attached Thumbnails Attached Thumbnails phase detector.jpg   pd_outputs.jpg  

  4. #4

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    A screenshot of the logic analyzer showing the pulse generator working (to fool it into thinking it's getting 3 phase even though it isn't), and a youtube video showing the drive powered up with no errors. Of course it's not connected to the NC controller yet (I need to put some other wiring back in place before I power up the axis servo drive and NC controller), so the machine ready signal is missing, but it should be good to go!

    https://www.youtube.com/watch?v=N5XUHMVhXh8
    Attached Thumbnails Attached Thumbnails phase_pulses_generated_ver2.jpg  

  5. #5
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by hwgasdfasdf View Post
    A screenshot of the logic analyzer showing the pulse generator working (to fool it into thinking it's getting 3 phase even though it isn't), and a youtube video showing the drive powered up with no errors. Of course it's not connected to the NC controller yet (I need to put some other wiring back in place before I power up the axis servo drive and NC controller), so the machine ready signal is missing, but it should be good to go!

    https://www.youtube.com/watch?v=N5XUHMVhXh8
    And then the next Problem you will have is that each Axes Drive will fault as well with the same problem of Phase loss detection, that can be over come as well but one wrong connection and you are going to have some expensive parts to replace

    Why don't you just buy a Phase Perfect and you would be running, this machine is never going to be happy running on single phase
    Mactec54

  6. #6

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by mactec54 View Post
    And then the next Problem you will have is that each Axes Drive will fault as well with the same problem of Phase loss detection, that can be over come as well but one wrong connection and you are going to have some expensive parts to replace

    Why don't you just buy a Phase Perfect and you would be running, this machine is never going to be happy running on single phase
    Heh, nope, the axes drive has no phase detection. All I had to do was move the connection to the transformer that supplies the low voltage for the logic control to a phase terminal that I was going to supply, and it fires up and works fine:

    https://www.youtube.com/watch?v=vok0GHZB8h0

    The Phase Perfect essentially does the exact same thing the axes drive, or spindle drive already does. It takes 1 phase AC and rectifies it to DC, then uses IGBTs to generate 3 phase AC from the DC bus. Why do I need to start at 1 ph 240VAC, convert to DC, convert to 3 phase AC (inside the Phase Perfect), then convert to DC again, and convert back to 3 phase AC (in the spindle / axes drive)? Every time you convert, the efficiency goes down. The phase perfect has a DC bus in the middle, and so does the spindle and axes drive! If anything, I'll add more capacitors to the DC bus, if I ever have problems with the bus voltage falling under load.

    The only thing actually in the machine the really needs 3 phase is the coolant pump, and I'll just get a cheap VFD to run that. It's not a very big motor, and It's going to be quite a while before I'm ready for coolant anyways.

    The one problem I have now is the regenerative breaking in the spindle drive is not happy, because my fake phase pulses aren't actually aligned with the incoming power. Well, maybe spindle bearings too - I'm no expert, but they sound a bit on the rattly side!

    Can the Phase Perfect deal with the spindle drive shoving power back to "the (virtual) line" for breaking? How much is a 50A or 70A (at single phase 240V) Phase Perfect going to set me back? I paid next to nothing for the machine, relatively speaking. It cost more in forklifts and trucks to move it than the actual machine itself. All told, machine and moving cost much less than I've seen people sell bridgeports for on craigslist! I got it cheap because the spindle drive was pretty damaged and completely dead when I got it. Frankly, not many people would've been able to diagnose and repair it to get it running at all, so I'm not too afraid of a challenge / having to replace a couple more IGBTs if something goes awry! I can probably buy a ton of replacement IGBTs for the cost of the Phase Perfect!

    I see a couple of solutions:
    1) Align my fake phase pulse generation I'm feeding into the drive with the actual phase of the input AC. Experiment with unequal phase pulses (if the drive will allow that) to better align the fake "3 phase" 120 degree separated pulses with the real 180 phase difference between my actual split phase 240VAC. At first I didn't get why they had 6 pulse channels in the phase detection, but now I see it's so they know when to switch on which IGBTs in the "regenerative" side of the drive to dump power from the DC bus back to the line when the motor is breaking. Makes total sense!

    OR

    2) Replace "the line" on the regenerative converter side of my drive with a breaking resistor (aka, stove element), like a Haas spindle controller (and probably lots of others) use. Then the timing of the phase detection pulses and the line voltage doesn't matter. Basically just end up with 6 IGBTs dumping the excess power to the resistor (heat), rather than trying to be fancy and shove it back to the line.

  7. #7
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by hwgasdfasdf View Post
    Heh, nope, the axes drive has no phase detection. All I had to do was move the connection to the transformer that supplies the low voltage for the logic control to a phase terminal that I was going to supply, and it fires up and works fine:

    https://www.youtube.com/watch?v=vok0GHZB8h0

    The Phase Perfect essentially does the exact same thing the axes drive, or spindle drive already does. It takes 1 phase AC and rectifies it to DC, then uses IGBTs to generate 3 phase AC from the DC bus. Why do I need to start at 1 ph 240VAC, convert to DC, convert to 3 phase AC (inside the Phase Perfect), then convert to DC again, and convert back to 3 phase AC (in the spindle / axes drive)? Every time you convert, the efficiency goes down. The phase perfect has a DC bus in the middle, and so does the spindle and axes drive! If anything, I'll add more capacitors to the DC bus, if I ever have problems with the bus voltage falling under load.

    The only thing actually in the machine the really needs 3 phase is the coolant pump, and I'll just get a cheap VFD to run that. It's not a very big motor, and It's going to be quite a while before I'm ready for coolant anyways.

    The one problem I have now is the regenerative breaking in the spindle drive is not happy, because my fake phase pulses aren't actually aligned with the incoming power. Well, maybe spindle bearings too - I'm no expert, but they sound a bit on the rattly side!

    Can the Phase Perfect deal with the spindle drive shoving power back to "the (virtual) line" for breaking? How much is a 50A or 70A (at single phase 240V) Phase Perfect going to set me back? I paid next to nothing for the machine, relatively speaking. It cost more in forklifts and trucks to move it than the actual machine itself. All told, machine and moving cost much less than I've seen people sell bridgeports for on craigslist! I got it cheap because the spindle drive was pretty damaged and completely dead when I got it. Frankly, not many people would've been able to diagnose and repair it to get it running at all, so I'm not too afraid of a challenge / having to replace a couple more IGBTs if something goes awry! I can probably buy a ton of replacement IGBTs for the cost of the Phase Perfect!

    I see a couple of solutions:
    1) Align my fake phase pulse generation I'm feeding into the drive with the actual phase of the input AC. Experiment with unequal phase pulses (if the drive will allow that) to better align the fake "3 phase" 120 degree separated pulses with the real 180 phase difference between my actual split phase 240VAC. At first I didn't get why they had 6 pulse channels in the phase detection, but now I see it's so they know when to switch on which IGBTs in the "regenerative" side of the drive to dump power from the DC bus back to the line when the motor is breaking. Makes total sense!

    OR

    2) Replace "the line" on the regenerative converter side of my drive with a breaking resistor (aka, stove element), like a Haas spindle controller (and probably lots of others) use. Then the timing of the phase detection pulses and the line voltage doesn't matter. Basically just end up with 6 IGBTs dumping the excess power to the resistor (heat), rather than trying to be fancy and shove it back to the line.
    I'm well aware of what is needed, you got lucky because of the age of the machine that the drives don't have phase loss detection, the VFD on that size machine normally always have phase lose detection

    What you normally do for the VFD Drive is you feed L1 R and L2 S and jumper L1 R to L3 T that's the correct way to do it, your regen could still be a problem, if it can't dump the excess energy

    You would have to talk to Phase Perfect I have one that cost $7500 works like a charm , if you smoke the Drive bad enough you are looking at some serious dollars they are not always repairable
    Mactec54

  8. #8

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by mactec54 View Post
    ... if you smoke the Drive bad enough you are looking at some serious dollars they are not always repairable
    I know the repair costs when you send it "somewhere" to get it fixed are crazy. So far I've put a grand total of $50 of parts into the drive, more than 10% of that shipping on one order that was really slow [side-eye glance at you Digikey US, where for the cost of next morning shipping which is standard at Digikey Canada, you get to wait a week!], and quite a bit of somewhat advanced soldering and PCB repair skills. It helps to be able to do things yourself!

    I guess you'd somehow have to factor in the time and money spent on a grad degree in ECE, all the test equipment and soldering equipment I've bought over the years, and all the time I've spent diagnosing and fixing all sorts of busted stuff too, but that sounds like work, and this is a hobby project!

  9. #9

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by mactec54 View Post
    I'm well aware of what is needed, you got lucky because of the age of the machine that the drives don't have phase loss detection, the VFD on that size machine normally always have phase lose detection
    Also, if you read my posts above, the spindle drive definitely HAS phase loss detection - the whole point here was I figured out how to work around it, but now it needs some adjustments to get the regen working properly!

  10. #10
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by hwgasdfasdf View Post
    I know the repair costs when you send it "somewhere" to get it fixed are crazy. So far I've put a grand total of $50 of parts into the drive, more than 10% of that shipping on one order that was really slow [side-eye glance at you Digikey US, where for the cost of next morning shipping which is standard at Digikey Canada, you get to wait a week!], and quite a bit of somewhat advanced soldering and PCB repair skills. It helps to be able to do things yourself!

    I guess you'd somehow have to factor in the time and money spent on a grad degree in ECE, all the test equipment and soldering equipment I've bought over the years, and all the time I've spent diagnosing and fixing all sorts of busted stuff too, but that sounds like work, and this is a hobby project!
    Well you are not the only one that has degrees, and you don't need a degree to do this type of work

    I think if you play with the DC Braking and deceleration Parameters, you may over come your problem it just won't stop as fast, and take the load of the regen
    Mactec54

  11. #11
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by hwgasdfasdf View Post
    Also, if you read my posts above, the spindle drive definitely HAS phase loss detection - the whole point here was I figured out how to work around it, but now it needs some adjustments to get the regen working properly!
    Just wiring it the way I said gets around the phase loss detection have done lots of machines this way, very elementary stuff
    Mactec54

  12. #12

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by mactec54 View Post
    Just wiring it the way I said gets around the phase loss detection have done lots of machines this way, very elementary stuff
    I tried that initially, it didn't like it - it still came up with the phase loss alarm.

  13. #13
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by hwgasdfasdf View Post
    I tried that initially, it didn't like it - it still came up with the phase loss alarm.
    Something else going on then, I have been doing it this way for many years and have never had it not work, what VFD Drive model do you have
    Mactec54

  14. #14

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by mactec54 View Post
    Something else going on then, I have been doing it this way for many years and have never had it not work, what VFD Drive model do you have
    Mitsubishi Freqrol FR-SF-2-22K. I thought I had mentioned it in the first post, but I guess I didn't actually put the full model number there.

  15. #15
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Most likely it has to see three separate phase potentials, if using single phase for three inputs, you don't see three potentials, just one, using three is how a phase rotation meter works.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  16. #16

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by Al_The_Man View Post
    Most likely it has to see three separate phase potentials, if using single phase for three inputs, you don't see three potentials, just one, using three is how a phase rotation meter works.
    Al.
    It definitely comes down to the regenerative breaking, which is essential to the drive's operation (and they couldn't be bothered to write some extra code to make it work for single / split phase in the firmware). Here's a link to the SPICE simulation where the forum didn't kill the quality of the graphics as an attachment:
    https://photos.app.goo.gl/jAvuJr2S3UyYaKN17

    The input power is at the bottom. What the 2 traces at the top do (the digital signals that go to the optocouplers that feed back to the logic side) is show it which phase is the "most positive" and which phase is the "most negative" at any given time. It uses that information to turn on the right "regen" IGBTs when it's trying to lower the DC bus voltage during breaking (using the line to sink power back to, rather than extract it from). There's also an interesting relationship between the phase of the incoming power and the pulse - the pulses happen before, but close to the peak of the input waveform, and last until the next phase is almost at its peak.

    Example, looking at the first full positive phase pulse, I(D15), which is telling it when phase A is the "most positive". That pulse comes up when input phase A (wrt phase B) is 216V roughly. That pulse remains active until phase B (wrt phase C) is 216V too, then phase B becomes the "most positive". The 3 "positive peak" pulses tell it which phase of the incoming power to connect to the positive side of the DC BUS during breaking (which regen IGBT to turn on). So during regen, it connects the positive side of the bus to Phase A B C according to those positive peaks.

    The same is true for the negative phase pulses, I(D16), I(D17) and I(D18), and connecting the negative side of the DC bus to which phase to dump power. Of course because it's 3 phase, the most negative phase is out of phase with the most positive phase, and those pulses transition directly in the middle of the "most positive" phase pulses.

    So during regen, it goes like this:
    Code:
             Connected to what side of the DC BUS
    Phase A  |  P  |  P  |     |  N  |  N  |     | 
    Phase B  |  N  |     |  P  |  P  |     |  N  |
    Phase C  |     |  N  |  N  |     |  P  |  P  |
             ---------------------------------------
             time -->
    So in every state, the P side of the bus is connected to one phase, and the N side is connected to the correct phase to bleed power back to the line.

    If the phase pulses aren't actually aligned with the line voltage, now you're connecting the P side of the bus to what you think is the "most positive" input phase, but in reality the voltage might be a lot lower, too much current flows from the bus to the line, tripping the Alarm 25 "Converter over current" alarm, and the drive shuts down and protects itself.

    I'm going to see how much I can reduce the phase shift between the N and P pulses (to better match to 180 degree phase shift split phase) before the drive goes "hey, wait, that's not 3 phase" and throws the phase alarm again.

    I'm also going to see how short I can make the Phase B pulses (making the phase A and C pulses longer to compensate, as those are the phases I'm putting the 240V split phase on) before it refuses to detect it as 3 phase as well.

    Depending on what the limits are of what it considers "valid" 3 phase, it will either work well and be a reasonably good match to the split phase 240, or I will switch to dumping the power into resistors, rather than back to the line, and then the phase alignment makes no difference at all!

    Working on making the microcontroller code that generates the pulses paramaterized, so I can shift the negative pulses with respect to the positive pulses in real time, as well as decrease the length of the "B" phase pulses, and see how far I can get before it throws Alarm 26 (missing phase) again.

    I.E. I need it to look as close as possible to this:
    Code:
             Connected to what side of the DC BUS
    Phase A  |  P  |  P  |as sh|ort  |  N  |  N  |
    Phase B  |     |     |as po|ssibl|     |     |
    Phase C  |  N  |  N  |<----|---->|  P  |  P  |
             ---------------------------------------
             time -->

  17. #17
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by hwgasdfasdf View Post
    I tried that initially, it didn't like it - it still came up with the phase loss alarm.
    I think what you are trying to do is going to be quite a challenge as the power requirement for single phase for a 30Hp VFD would be substantial A 12Hp to 14Hp for a single phase supply is pushing the limit 7Hp to 10Hp is normally OK

    I did not realize that you where trying to run a 30Hp straight off Single Phase, this kind of thing is what dreams are made of
    Mactec54

  18. #18

    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by mactec54 View Post
    I think what you are trying to do is going to be quite a challenge as the power requirement for single phase for a 30Hp VFD would be substantial A 12Hp to 14Hp for a single phase supply is pushing the limit 7Hp to 10Hp is normally OK

    I did not realize that you where trying to run a 30Hp straight off Single Phase, this kind of thing is what dreams are made of
    It's a 30HP (22kW) VFD, but only a 15HP (11kW) motor, and only 15HP for 30 minutes. 10HP (7.5kW) continuous, and I doubt I'll ever be taking 10HP cuts with it. I said that in the very first post.

    Seeing as I'm not really getting any help here, and just a lot of naysaying, and speculation without even reading what I've written, I think I'll continue documenting this elsewhere.

  19. #19
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    Quote Originally Posted by hwgasdfasdf View Post
    It's a 30HP (22kW) VFD, but only a 15HP (11kW) motor, and only 15HP for 30 minutes. 10HP (7.5kW) continuous, and I doubt I'll ever be taking 10HP cuts with it. I said that in the very first post.

    Seeing as I'm not really getting any help here, and just a lot of naysaying, and speculation without even reading what I've written, I think I'll continue documenting this elsewhere.
    Good luck tell everyone what you are doing to start with, I have been doing this for a long time and repair VFD Drives and I know how it is going to end, so why does it have a 30Hp VFD Drive if you have only 10Hp continuous rated motor, 30Hp VFD most likely may never run on 230V single Phase in fact it is ridiculous to think other wise, it would need 90A using 240v 3Ph so around 120/125A supply for single phase that would need a cable size of 1/0 minimum, I would say you will be wasting everyone's time no mater where you go

    I'm not a naysayer, I'm told you what you needed to do in the first 2 Posts you need a phase converter and a 200A supply to run this beast on single phase, I don't care what anyone tells you 30Hp VFD running direct on single phase it's not going to happen
    Mactec54

  20. #20
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    Re: Mitsubishi Freqrol FR-SF on Single Phase?

    I have built Rotary Phase convertors and they work fine. Your going to need about 50 amps on 240 volts to run a 15 Hp motor on single phase. Lot simpler that trying to run it off a VFD that was never intended to run on single phase input.

    Correction 15 Hp motor here>851150.00 LEESON 15HP MOTOR C256K17FB1A

    Draws 58 amp.... on 230 volts.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router Mach4 Kimber 1911 45ACP

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