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  • Need help with simple system design

    Hopefully im writing this in the right area. I need help designing what I think is a fairly simple system. I need to control a 5HP motor via a contact. When the contact closes I need it to turn on the motor and remain on until the contact opens. When the contact opens I need a timer to be initiated for 30-45 seconds. When the timer expires I need the motor to shut off. However I also need it so if the contact closes WITHIN the timer countdown period to clear the timer, keep the motor running and when the contact opens restart the timer.

    Preferably I would like the motor to soft start (I think this is where a VFD would come into play) The motor specs are a Baldor 5HP Single Phase 1750RPM 184T Frame. I dont need to vary the RPMs, I just need the motor to turn on/off when the contact closes and shuts off when the timer expires. If you could please let me know how I can do this I would greatly appreciate it! I would also like a manual override option, so I can either use the contact On/Off or just manually turn the motor on! I want it to look nice too so an enclosure with buttons would be great too!

    Please let me know what products I would need to purchase to make this happen and also the steps needed to make this happen! Thanks in advanced!


  • #2
    While I haven't used one, Automation Direct's GS4 drive has "a built-in PLC" which sound like it might be good for your application, but again, I haven used one so I don't know the capabilities. I seems the only way to find out is to actually install the configuration software and hope it has a help file, I couldn't fine any other real documentation.. The drive manual has only a very abbreviated description of the GS logic function, it doesn't even say if the thing has timers, but what kind of "PLC" doesn't have timers?

    While a GS4 sounds like it should simplify the wiring, a GS2 and a CLCIK PLC would probably cost less

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    • #3
      Thanks, I wrote the GS2 off because it doesn't seem to have an option todo single phase 230 up to 5 HP. Looks like they only go up to 3.5 HP The GS4 option that would work with my application is $910 bucks....Ouch!

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      • #4
        1. You can't "soft-start" a single phase motor. There are capacitors on the motor that need the full voltage to excite the rotor so it will start turning. VFD's start out by reduced voltage and frequency to soft-start the motor.

        2. Go with pushbuttons, a WEG contactor & motor protector, and use a CLICK PLC. You'll like spend around $200, and you'll be able to do what you want and expand into more control in the future.

        If you've done the very best you can, worrying won't make it any better - Walt Disney

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        • #5
          Oops! I missed the "single phase" Ridgeline is right, one can't soft start a single phase motor, but you are in luck, Automation direct sells motors too! Well, sure, that will double your "Ouch!"

          How often will this motor be starting? if it is fairly infrequent, then a conventional starter will be a far less expensive option, however if it is starting and stopping very often a single phase motor may not be too happy.

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          • #6
            If you go with just using a contactor and CLICK PLC like I suggested, here is the PLC program that will work like the operation you described.

            I have included the part numbers of the items needed in the rung comments.
            Attached Files
            If you've done the very best you can, worrying won't make it any better - Walt Disney

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            • #7
              Thanks for the info guys! Very much appreciated! I didn’t know a single phase motor couldn’t be soft started! The motor won’t run much. At most twice a month for maybe a total of 1.5 hours. But in that time it could be cycled on and off 10-15 times!

              I downloaded the software and got into the the rung comments. I’ve added them to my cart. I would also like an enclosure for this. An on/off button and a manual override “switch” and an “auto” switch. Lighted feedback would be cool but not necessary if it complicates things. Also I assume I just need the most basic click PLC?

              I understand wiring but have limited knowledge of motors and how they connect up with the contactor, over ride, thermal resistor etc. My day job is home and corporate building automation. I have hooked up motors before but never designed a system like this.

              Once again, I very much appreciate your guy’s input and help!

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              • #8
                Or, for $146.00, you could get a C-more micro 3" panel (EA3-S3ML-R) and this cable (DV-1000CBL $19.00), and use it to make as many pushbutton/switches as you like. The programming software for the C-more micro is free.
                If you've done the very best you can, worrying won't make it any better - Walt Disney

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                • #9
                  If you really need the soft-start but are asking for single phase on account of your available power, find a drive that will take single phase input power and create three phase for the motor. Then you can soft start. It's not well advertised, but ABB ACS-550s will do single phase in, three phase out up to much higher currents than I've seen in other drives that will do that. You do need to derate the VFD amps significantly as you're not using the incoming line rectification components very efficiently.

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                  • #10
                    Originally posted by Ridgeline Mach View Post
                    Or, for $146.00, you could get a C-more micro 3" panel (EA3-S3ML-R) and this cable (DV-1000CBL $19.00), and use it to make as many pushbutton/switches as you like. The programming software for the C-more micro is free.
                    That seems like a good solution, but doesnt it also require the Click PLC? so im programming two things?

                    If I go this route it would be:

                    Enclosure-C-More-Contactor-Overload protection-Click PLC-Transformer to power the Click/C-More, some fuses and misc. wiring right?

                    C-More connects to the Click somehow, Click then wires to the contactor and then the contactor-overload protection etc out to the motor?

                    Thanks!

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                    • #11
                      Instead of the Click (with display?) how about one of the multi-mode timers on this page? https://www.automationdirect.com/adc...z-_Tachometers 3PedalMINI just read the specs and the timing diagram for the Delay Off (SF) mode. It sounds like what you described.
                      thePLCguy

                      Bernie

                      Comment



                      • #12
                        Originally posted by bcarlton View Post
                        Instead of the Click (with display?) how about one of the multi-mode timers on this page? https://www.automationdirect.com/adc...z-_Tachometers 3PedalMINI just read the specs and the timing diagram for the Delay Off (SF) mode. It sounds like what you described.
                        Ohh, I like! It seems simpler. is if it has the ability wo when contact closes WITHIN the timer countdown period to clear the timer, keep the motor running and when the contact opens restart the timer.

                        I read a few of them and im not sure if im missing it or if I just haven't found one with the low voltage contact input? unless they all have it? I assume this would go Timer-Contactor-Thermal OverRide relay out to motor?

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                        • #13
                          Originally posted by 3PedalMINI View Post

                          Ohh, I like! It seems simpler. is if it has the ability wo when contact closes WITHIN the timer countdown period to clear the timer, keep the motor running and when the contact opens restart the timer.

                          I read a few of them and im not sure if im missing it or if I just haven't found one with the low voltage contact input? unless they all have it? I assume this would go Timer-Contactor-Thermal OverRide relay out to motor?
                          Purchase a timer with relay output, like any MS4xx-xx-xxx so that the voltage of the motor contactor is not dependent on the timer's output voltage or type.
                          If you've done the very best you can, worrying won't make it any better - Walt Disney

                          Comment



                          • #14
                            Thanks guys! I’m sorry for all the questions. I know this stuff is very easy for you guys. This is exactly what I’m trying to remake. Sounds like the timer/relay is exactly what is in this system. The relay/timer in this pic is Potter brumfield but appears to be discontinued. Can you link me to what AD has that would be similar: again, I really appreciate everyone’s time and input!
                            Attached Files
                            Last edited by 3PedalMINI; 07-15-2018, 01:39 PM.

                            Comment



                            • #15
                              Originally posted by 3PedalMINI View Post
                              Thanks guys! I’m sorry for all the questions. I know this stuff is very easy for you guys. This is exactly what I’m trying to remake. Sounds like the timer/relay is exactly what is in this system. The relay/timer in this pic is Potter brumfield but appears to be discontinued. Can you link me to what AD has that would be similar: again, I really appreciate everyone’s time and input!
                              Use this one: https://www.automationdirect.com/adc...)/MS4SM-CE-ADC
                              If you've done the very best you can, worrying won't make it any better - Walt Disney

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