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Baldor 3-phase motor for RPC

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  • #16
    I tried to get American Rotary to give me some hints on how to verify if the starter contactor was not kicking in.
    They said my description made it sound like either bad start caps or bad start contractor, but they just wanted to sell me a new panel (Big help, thanks guys). So no schematic, no voltage readings on the fake leg at start-up, no nothing.
    The Fitch design schematics doesn't help much in that there's no separate transformer, there's four contactors and a PCB. My next step is to dissect this thing and reverse engineer to do a schematic (I've done it too many times on trucks with no schematic, it's time consuming and frustrating). I'm thinking the mini contractor is the start contactor and the three that seem to work together might be the run contactors. Considering the three run about $260/each and the single mini runs $80/each I'd rather the start be the single mini.
    I don't know if anyone has cracked one of these open, but it would be nice to have replacement parts ordered and arrived before I spread this thing across a workbench in 50 pieces just to map out the wires and figure out what no one wants to tell me that built the damn thing.
    You may only view thumbnails in this gallery. This gallery has 5 photos.

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    • #17
      So, does anyone know about Schneider Electrical Contactors?

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      • #18
        Fear,


        You should be able to find the coil terminals for each individual contactor and from the bench test energize each contactor and see if it works, that would be a start. You may not need to replace any of them. I just worked on one that the PC timer board died and we just set it up as a manual start with a momentary switch tied to the start-cap relay, then it went to run and all was fine. Just don't want the operator to hold the switch to long.
        As to tracing the wiring and making a diagram, can you use a multi meter and just disconnect one wire or terminal at a time and then reconnect vs disassembling the whole thing? Might save a headache later. Also If you do take it a part, take LOTS of pictures as these will bail you out in the end.

        Let us know how you make out.

        TX
        Mr fixit for the family
        Chris

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        • #19
          Most industrial contactors have replaceable or repairable coils and contacts, so you should be able to fix them unless they are badly damaged. Schneider is a well-known and respected name so you should be able to find replacement parts.

          https://www.grainger.com/category/el...ters=brandName

          https://www.se.com/ww/en/product-cat...ection-relays/
          http://pauleschoen.com/pix/PM08_P76_P54.png
          Paul , P S Technology, Inc. and MrTibbs
          USA Maryland 21030

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          • #20
            Originally posted by Fear View Post
            From looking online, I'm pretty sure the little "J"-wires for a thermo sensor and using them is completely optional.

            I got the American Rotary panel from another member of the forum and it's sized for a 40HP motor. I can't say how grateful I am, that was awesome. I had to replace some blown start capacitors. I found some NOS American-made ones (all new ones I could find were from China). I soldered the same rating resistors as were soldered to the old ones. I asked American Rotary for a schematic and they couldn't help me because the panel was very old and from many revisions ago. the best they could do was pass me some pictures of another identical panel from the same time. This panel is, I believe, from before American Rotary started getting together with Baldor to make special runs of motors more suited for RPCs. The motor was brand new. I found it in a warehouse in Alabama with a missing fan cover and wiring box and a broken cooling fin but with all the paperwork straight from Baldor. These things typically cost thousands, I got it for a couple hundred and a little footwork to find another fan cover. It spins freely by hand.

            This is a learning exercise. I'm a very competent electrical technician on automotive applications but this has been a fast crash-course on understanding 3-phase and RPCs with communication with American Rotary, members of this forum and plenty of reading material being my only teachers. I quickly found out all the self-professed "commercial electricians" I know don't know squat about 3-phase or much else that I can find useful.

            American Rotary has a symptom/solution checklist and one of the suggested solutions was to add capacitors if it needs it. There's also reversing the input single-phase wires, checking voltages, etc. I know I'm close to this working right, it wouldn't be realistic for a rookie's first RPC build to be plug-n-play without a few bumps in the road.


            This is a picture of the 40 HP Baldor motor your panel ran. The second picture is the motor tag.

            Edit to add > The original unit was ordered in June 2011 if that would help in getting wiring diagrams from American Rotary.
            1 Soft Starting Digital Rotary Panel with Starter, 40-50HP, 240volt

            The replacement ADX model panel was ordered July 2014.

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            Click image for larger version  Name:	40 hp Motor tag.jpg Views:	0 Size:	46.6 KB ID:	1873947


            Last edited by Ridgerunner; 05-08-2020, 06:21 PM.

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            • #21
              Picture of the inside of the 40 HP ADX panel. Maybe not the same as the old panel. The last 2 are of a 25 HP panel. Let me know if you would like any other pictures.

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              Here are 2 pictures of the inside of a 25 HP panel. Don't know if it would help.

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              • #22
                Once again, I appreciate it.

                When I read through the Fitch Converter pages, just having the housing and contactors and run capacitors is most of the cost in building a RPC. So if the PCB is shot and I have to tear it down to reverse-engineer a schematic, I'm still miles ahead of having to make an enclosure and gather parts myself. I'm just shy about running 240v A/C test leads to bench test, but I'll need to get over that. I'm used to bench testing 12v D/C components that are less-likely to do anything worse than let a little smoke out.

                I'll get this figured out. I'm this close and I have learned so much in so little time with this project. Most dudes in their 40's just want to stick to being topped-out in their field of expertise and are too proud to start over in something they know very little about. It's like getting into bluegrass after spending 30 years just listening to rock.

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                • #23
                  Was gonna say, if you aren't aware of it already, there is a entire forum devoted *just* to RPC's and VFD's at PM here: https://www.practicalmachinist.com/v...rters-and-vfd/

                  Might want to check there

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                  • #24
                    So Fear, Where is home for you? Maybe there is someone close enough that does have more experience that you could get together and practice social distancing and figure out your problem. If you don't want to post your exact location a town might be enough. Also your profile has a place to put where your from.

                    Can you tell us the history of this unit? You say it had bad capacitors that needed to be replaced, did it run with the previous owner that you got it form? This night be a clue to the electronics and there not working?

                    Anyway to proceed. When working with the 240v, make up a power cord and a double pole switch, then add leads to the contactor coil, the safe way to do it then is operate the switch and stand back, also wear safety glasses as we only get one set of eyes and there aren't usable replacements. As Paul said you can get replacement coils if any are bad, but I doubt they are, its in the electronics that things are not working if I were to take a guess.

                    You can also collect the micro farads and voltages of the capacitors and post those, then we can tell you which are start and run capacitors if that's a question. Then it's just checking the contactors for operation without voltage to the contacts, you just need to operate the coil to see if each one operates. Then it's a matter of wiring around the electronics and making it a manual operation with a switch or simple automated RPC vs using the electronics at all since it sounds like they may be not working.

                    Keep us posted, and we can get this going for you together.

                    TX
                    Mr fixit for the family
                    Chris

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                    • #25
                      When working on mains-operated equipment, it is helpful to use a Variac with a fast-acting fuse or circuit breaker rated at maybe 2-3 amps, along with a voltage and current meter to see if there is a major problem as you raise the voltage to the point where it should start working. You can also manually operate the contactors if you know how they are supposed to work. Safety goggles are always recommended, and perhaps a full face shield. And a foot-operated deadman switch is another safety precaution that might save your bacon if the fit hits the shan.
                      http://pauleschoen.com/pix/PM08_P76_P54.png
                      Paul , P S Technology, Inc. and MrTibbs
                      USA Maryland 21030

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                      • #26
                        Originally posted by Mr Fixit View Post

                        Can you tell us the history of this unit? You say it had bad capacitors that needed to be replaced, did it run with the previous owner that you got it form? This night be a clue to the electronics and there not working?

                        TX
                        Mr fixit for the family
                        Chris
                        Ridgerunner, who posted around your posts is where I got it. Super great guy, he was running it until the caps blew. He talked to American Rotary and they sold him an upgraded panel, so he passed this panel on to me. Whatever problem blew the caps then seems like is still an issue now.
                        I was thinking a sticking start contactor killed the start caps, now you have me looking at the PCB.
                        I live in southern middle Tennessee. The only dude around here that seems to know anything about 3 phase motors and RPCs is a dude that runs a business on the other side of the nearest town rebuilding electric motors and replacing well pumps. The dude comes off as one of those grizzled country boys that's easily provoked. I don't picture him getting his own children's show any time soon. If I get any help from him it would have to involve money and I'm not at that point yet.
                        Everyone else was full of expertise as "used to be a commercial electrician" until I actually needed direction. Then they start talking and I realized I passed them up just doing my original research when I ran the 400a service to my shop.
                        I was a truck mechanic for over 20 years and electronics was one of the places where I felt I truly shined. I've soldered together many harnesses from scratch and solved many factory wiring issues on customers trucks.

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                        • #27
                          Fear-
                          What PCB, not seeing one in your images? Have you traced the wiring for the start caps? Is one of the contactors used to take the start caps out of the circuit? That contactor is energized how? What sends power to that contactor coil?

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                          • #28
                            Originally posted by Mr Fixit View Post
                            Fear,


                            You should be able to find the coil terminals for each individual contactor and from the bench test energize each contactor and see if it works, that would be a start. You may not need to replace any of them. I just worked on one that the PC timer board died and we just set it up as a manual start with a momentary switch tied to the start-cap relay, then it went to run and all was fine. Just don't want the operator to hold the switch to long.
                            As to tracing the wiring and making a diagram, can you use a multi meter and just disconnect one wire or terminal at a time and then reconnect vs disassembling the whole thing? Might save a headache later. Also If you do take it a part, take LOTS of pictures as these will bail you out in the end.

                            Let us know how you make out.

                            TX
                            Mr fixit for the family
                            Chris
                            Okay, the contactors seem pretty simple. The run relays just connect L1 1ph to L1 3ph and L2 1ph to L2 3ph and theres a start contactor that has power from L1 to start caps to contractor to L3 all on the 3ph side. Just connect the two legs of 1ph to two legs of 3ph and then zap it from caps energized off the L1 to the fake leg to get it started.

                            The timer board has me confused. Bypassing it would mean a NC stop pull switch off L2 1ph to a momentary start switch for the run contactors and a second momentary for the start contactor or what?

                            Maybe the NC pull stop spliced to both leads on the run relays and a momentary NO switch to the start relay. What ratings on these switches?

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                            • #29
                              Originally posted by reggie_obe View Post
                              Fear-
                              What PCB, not seeing one in your images? Have you traced the wiring for the start caps? Is one of the contactors used to take the start caps out of the circuit? That contactor is energized how? What sends power to that contactor coil?
                              Twisted orange leads go to some box in the timer PCB from the run contactor. The left black goes to the start button, the right black goes to the run contactor, the white to the start contactor, the red to the L2 single phase bar and the blue to the T3 "fake-leg" bar.
                              The white lead triggers the start contactor to dump power collected from the T1 3ph bar and through the start caps to the T3 "fake-leg" bar.
                              The PCB gets command from the start button and activates the run contactors and is supposed to activate the start contactors briefly until the RPC starts turning sufficiently.
                              You may only view thumbnails in this gallery. This gallery has 2 photos.

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                              • #30
                                Fear,

                                Your post #15 in picture #2 there is a gray cable with 5 conductors connected to the terminal strip. Is this a switch on the front of the case? Does the switch have a OFF (lft) RUN (cntr) START (rt) and the start is a momentary in that when you let go of it it goes to center or run? If this is the case what is the voltage that goes to the coils of the contactors? You may need to pull one out of the cabinet to look on the side or top of the coil to read a voltage.
                                It may be that these are low voltage coils fed from the PC board power that is at the top of picture #3 in post #16 which is what controls all the contactors, the start contactor is the 1 sitting deeper into the cabinet in the same picture, this is your start contactor that puts the start capacitors in and then is deenergized by the release of the switch to run which the PC board keeps it in run. The low voltage switch communicates to the PC from the momentary contact of the switch to the run contactors which controls the run contactors and capacitors too.

                                So the one thing that you can do is use the switch if it is as I describe, to energize the start contactor and then let go and it puts the system in the run mode and all is good.. This is if the system is low voltage. If these are 240v coils then the switch will need to be verified that it is rated for this voltage which from the gray cable I doubt it, but they do make it in 300v rating so maybe it is.

                                You will need to check a few things and then let us know what you find. Keep us posted.


                                Coil link. https://www.se.com/ww/en/product/LC1...standard-coil/

                                TX
                                Mr fixit for the family
                                Chris
                                Last edited by Mr Fixit; 05-10-2020, 11:15 PM.

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