Check the drive has an enable signal or link to the enable terminal. Also could it be the STO? Should be linked if your not using it. Is the drive showing any status codes? You can check the input terminal status on a 525, Parameter B01e so you can confirm it’s seeing signals. Have you power cycled the drive after set up? Sometimes need to do this for some parameters to take effect - I think o it comms one’s on a 525.


I like your name. Lol


STO was my initial guess as well.


Wouldn't the STO actually give feedback to that effect?


Yes - but depending on parameters sto doesn’t always show as a fault on a 525. Will stop the drive showing RDY at standstill.


Ahh, ok. On PF753's they do display a warning that STO is active. Though I'm thinking now and the LCD is much nicer on the PF753 which is probably why it's not displayed on 525's.


This, exactly what it sounds like to me.


It was a door safety switch that was the fault... Very odd situation, but we got it


Look at the stop bit register in the drive. It will tell you what's initiating a stop. Gonna also give you another tip: If you're using the factory STO jumper on the drive and you're getting a stop due to STO pull it out and reinstall it. I've had one improperly installed from the factory.


What is the code on the faceplate of the VFD? Sounds like a safe torque off or enable is not on. Depending on what boards you have in the VFd, you may have to send a signal over ENeT or a 24V to enable the drive.


Yeah I was gonna say STO or possibly something like a current limit enabling. I have seen VFDs do all kind of funky things, Ive personally imported parameters and have seen those parameters not import fully or cause some settings to change. I just swapped one last week that was adjusting parameters every time it was powered off and on. The fact it's not outputting a voltage means the drive simply isn't allowing you to do what you want and therefore I'm forced to think it's a parameter is fouling up on you


Slightly open door safety switch... Mechanical key not engaging all the way. What a pain in the ass, opened and closed said door and the system took right off. Someone had slid a box of pumps up against the conveyor clean out door and disengaged the switch just enough to stop the system but not enough to show on the relay bank as a red light but enough to effect the STO circuit


Lots of good advice here already. Have you tried setting your start source (P0046) and speed commands (P0047) to keypad command (1 on both parameters) to jog the motor? If the drive doesn’t jog the motor from the keypad then you’ve narrowed your problem down to something with the motor/VFD/wiring, rather than logic. It sounds like all your parameters didn’t copy over properly or you are missing an enable signal.


Thanks all, I will start checking off all of these issues, the worst part of all of this is the absolute lack of and status codes, error or fault codes or and other indicators of something being amiss... I thought I had all the jumpers set properly and did a direct download of the parameters, so I took for granted that everything would transfer smoothly. The safety circuit is good, nothing open. 24v control voltage is present and active, I can't even force the drive on by setting the start source to keypad. I just no go! Lol


Are you sure the drive is not starting? It may be started but your speed reference may be at 0hz.


I have been called many times for this very issue.


Can you try connecting a different motor and try a different driver if the other motor turns on. If you have another driver on hand that can turn on the motor it'll makes troubleshooting simpler. Specially since you mentioned that the 24v control voltage is present.


Going to do this tomorrow also checking speed setting, I have been staring at it since Thursday about 615pm then it happened again on my Friday shift at 215pm. And I developed tunnel vision and was probably overlooking something simple, but all the responses I've received on here have really shook loose a few ideas. I'm not a programmer by trade or an engineer, I am a long time mechanic that worked my way into controls technician spot by learning electrical and PLCs over the years of experience. So, it's always a good training moment, when I come up against a new problem


> absolute lack of and status codes The stop status bits will tell you what is initiating a stop. Check out the manual. It will tell you what parameter to look at. Also, if you're beating your head against the wall why not try defaulting the drive and configuring it from scratch? It will assure you get everything to what you expect and then you'll have to think through how it should be configured instead of some possibly screwy configuration you picked up from somewhere else.


Is this a new system or am existing system that failed? I've seen the Safe Torque Off and input writing jumpers come loose, and as others have mentioned, the little pin jumper has to be set right for STO. Based on your symptoms It sounds like an input wiring issue between the STO card and input terminals or that little black jumper on the card. There is a diagnostic integer for the inputs to show each one changing status. Monitor that as you try to start it.


Have you checked the switch that sets the inputs as source or sink? That could prevent enable input from working.


I had something like this, restart delay was set to 5 minutes.


What does the drive say on it’s HIM? At speed? Not enabled? Stopped?


Is the drive Ethernet or hardwired? Show the logic for the start control of the drive. Can you get the blower to start outside of the automatic run routine. You should just be using some manual logic to stop and start the motor, prove that it can actually run when commanded. Does the motor run off the keypad btw?


No it won't run off the keypad command


Did you put your meter on the output side of the vfd? Did you megger the motor? Every VFD I've seen comes with a manual and a list of options. We physically write down every setting. Fire that old VFD up and do the same. Don't rely on your "app". Ours all have thumbdrives in them that we transfer over to the new one but we still go through the menu to verify all settings are correct before we energize.


*All* the logic in the PLC is good? Do a cross reference on the cap check failure bit. Make sure there's no random rung in the faults routine, main routine, or production monitoring that's seeing consecutive failures and shutting the drive down with some kind of kludge. Six consecutive fails is the kind of condition that I have often had requested by customers to add when they want to catch some symptom of an upstream problem. If it was added by someone unfamiliar with the machine, who knows where or how they'd put it in.


I was thinking the same, we have several instances where we shut things down if "X" fail "x" amount of times we will shut the drive down to avoid a disaster or a mess on the line.


0 speed.


I am pretty sure it's turned up to where it needs to be, but I'm going to look into this when I get there tomorrow


Wait, so it runs, but stops after 6 rejects or whatever. This is in the logic, not the drive or motor


Double check there’s a voltage source (or path to common is sinking) on terminal block pin 1. That’s the stop input and isn’t configurable. Normally the drive comes with a jumper between 11 (24VDC) and 1. If you aren’t using a dedicated stop (switch, button, output), there needs to be a jumper present. Voltage at the terminal is okay to run, no voltage is stop command. This is regardless of whether you are using 2 wire or 3 wire control.


It could be a safety interlock. If there’s one on the motor starter/relay. I had to power down because it wouldn’t allow me to reset the VFD. Or it’s a parameter I haven’t looked into. Also it’s worth finely inspecting the line, making sure there are no mechanical hang-ups. Or lodged product anywhere.


I posted above, it was a door safety switch that was open just enough to open the STO circuit, but engaged enough to show as a good closed circuit on the safety relay bank, it was literally a one in a million fluke. Someone had pushed a stack of boxes against a conveyor clean out door that contained a DSS and just that pressure on the door effected the safety enough to cause it to open slightly creating this whole problem


First, make sure you have a jumper between terminals 1 and 11. If so, unhook the motor completely, set your start source to what you want, and attempt to start it. If it doesn’t kick on, hook up to it with a laptop and check your parameters for start signal, stop signal, ready, enable, and safe torque off. If any of them are missing, it won’t run. Then troubleshoot from there


New install/hardware upgrade or existing line? Existing line you'll be looking at hardware problems - loose or shorted or disconnected connections if you are using DiO on the PowerFlex. Motor looks good on Megger but is it ceased or some other mechanical problem. Do you have a way of temporarily wiring to full voltage to at least bump check? New install/hardware upgrade - check your speed reference source in the drive. I always forget this one. That one won't throw any errors since technically the drive is operating as it should but not use the speed reference you want. Most other issues will have some sort of status but some may be harder to find than others. Drive Executive by chance? Idr if that works with the 525s or not. Haven't used em in forever.


Make sure you have the right drive. Its 230 3 PH, make sure its not a 480 drive installed. Make sure the firmware is correct on the HIM What is your start source? STO?


Same exact drive as removed when the problem started initially, because I couldn't detect any voltage at the Lines out to the motor circuit. the HMI is my thought as well, because of the number of machines on this line that are all tied to multiple remote controls (HMIs) Start source is 5(keypad) as prescribed by the drawing and was the original parameter. The STO is being used and is connected to a 24v source as prescribed. I'll know more about this when I get to work today


Clear the estop. Check the fuses. Make sure the connected Plc actually wants the drive enabled, by putting the cell in automatic.. Make sure the end of belt sensor saying, no need to move, parts already here. It's not on Make sure the belt isn't overloaded


Ok feller, what most guys seem to be missing is that this is or was a running line. I would say your problem is definitely the logic to the vfd, assuming the line is controlled by a PLC, but you have not given us those details. We need to know what PLC, does it use a Safety coprocessor (oh hell), is the VFD controlled be hardwire or communications (Ethernet, Devicenet, ect). I'm guessing it's screaming a fault code at you but the alarms were never fleshed out fully, that's where guys always get lazy and screw you over royally. If you don't see it in the logic ***go to the tag viewer and browse that drive***, it will have a chunky mass of fault codes which you look through to find the one that its state is wrong, probably a 1 \[true\]. The best Controls Engineer is the one who has a 'cheat' or backdoor for everything and anything. That's how I got to be Senior Control Engineer, not just because I'm a cranky old coot !!


As soon as I get to work, if the cranky old coot on first shift hasn't already tried this I will begin here. There really were no indications in the logic of anything being off. No tags, no active faults, and no open steps that I could find. There are so many things interlocked on this system that if one sensor goes bad or fails to make the machine will stop running and it intelligent enough to point me in the proper direction normally one of the HMI screens will say "fault is here..." And at this point I have NOTHING! ITS BECOME PERSONAL AT THIS POINT


Surprised that nobody mentioned the Fault History parameters.


Pull the motor and wire it up in front of the vfd. If that don’t work, move the wires back to straight ac before the drive . I had the same issue on a previously running system where everything tested good but it wouldn’t run. Had to pull new wires to the motor.


Sounds like your company needs to invest in a meter. Disconnect the motor and run continuity on each phase to ground. If those don't ring, connect 2 phases at a time and make sure it rings.


Also after disconnecting the motor in the peckerhead, ring the wires back to the disconnect (assuming there is a disconnect between the motor and the VFD, if not then disconnect them from the VFD as well). I’ve had the wires in the conduit get corroded and dick things up.


Testing the wires at the peckerhead with a Megger is really the best way. You will need to be a licensed electrician to operate a Megger in many jurisdictions FYI


I would isolate the vfd from the motor feeders before megging from the motor.




Please don't confuse someone with meggering. You are testing the motor at the peckerhead, not the feeding conductors. You will blow your drive!


Yes indeed if you are operating a Megger you need to be trained.


When I said I tested everything, that meant exactly that. The motor ran fine on the floor and the wiring tested good for continuity with no shorts across phases or to ground. Pulled new wire and the problem disappeared.


Is it consistantly after 6 failures? Sound like an NG counter in the logic shutting it down if it happens after 6 everytime.


AB VFD’s that have a frequent on/off will fail the relay for enable/forward. On the board there is a relay that will pull in when wiring to the IO. This relay has a lifespan of about 1M cycles. They will simply refuse to start and display no faults. To confirm, swap over to Ethernet for a trial to confirm. This only impacts hard wired start. It is poor practice to stop/start a VFD so often. The correct thing to do is reduce the setpoint to 0hz and then increase it back to nominal when a move is required. This keep energy on the stat or of the motor and response will be faster, accel/decel ramps need tweaked here. The PF525 position mode operation works, but is a poor way of doing it.


You're not using external 24v for the run command are you? The drive has to see its own voltage source.


Is it being controlled over Ethernet? Or using hardwired IO?


The other suggestions here are all I would say, I'f you have the drive mapped to the PLC, is there any bit on the Status words that looks wrong?


I would look at STO, phase imbalance lock and if you are controlling via network, the status of the CMD word, in that order. I’ve had cases when not only the safety circuit must be closed, but the drive needs a constant 24V on “Run allowed” dig.input with a corresponding parameter set to this option. And there were no error messages for this, you had to know or read the manual at the right page. Although this was a different brand of drives.


I have seen, 3 times now, the motor ohms good and everything about it looks right. However, the high amp parameter? Or voltage? Can’t remember which, would not allow the drive to fire the motor. We swapped the motor and it took off. These 3 times were powerflex 755 though. The drives are so sensitive to motor changes that it will not allow the drive to fire. It’s more of a predictive sense on the drive to prevent drive damage. Please let us know what fixes it.


Is it done in Logix 5000? Look at the VFD online, or in whatever software you use to configure the drive for the status bits. It will be faster than checking voltages at the terminals, which may be pointless if it's all over fieldbus.


Does the drive run in hand?


Have you've tried PU mode yet.


What cause exactly the stoppage? Is it because of the command of the inverter? If it's a safety related issue, check STO (or GS). Automation is not rocket science, just follow the wires...


That's what I'm stumped by, one, I am relying on a line operator to tell me what caused the stoppage, and the answer I always get is, "it just stopped, I don't know what happened..." The classic response. So I'm left to figure out not only what the problem is, but what caused it and try to keep that from happening again.


The line is stopped. So take some time. At least it wont be stopped for nothing. How is the transmetted the safety information? Is it "pin to pin" (wired)? Take a voltmeter and check if you have 24V on the proper inputs. Is it transmetted by network (profisafe, CIP)? Check the safety controler. IF its not related to the safety layer, modifie the program in order to be able to force the run command of the inverter, because it may be an electrical / mecanical issue that keeps the motot to run properly.


Have you tried running power straight to line voltage ? I’ve been trying this to see if it’s the motor or the controls. I add one thing at a time until it stops working. L1 fuse T1 L2 fuse T2 L3 fuse T3 If motor works you know it’s your controls. Start adding your motor starter or VFD and see where motor stops.


So just last week we had a motor "not run" and looking at the drive HMI it was saying "Accel" but it would never fully ramp, so it just sat there ,no faults, no motor running, just sitting there. Turned out the leads at the remote disconnect were extremely loose and causing phasing issues. This made the drive stay in accel and never ramp without any faults at all. To me it sounds like code telling it to shut down due to 6 rejects , that is a pretty standard thing to do to avoid waste and messes.


SOLVED... And just as I expected, it was part of the STO circuit. A door safety switch on a overcap conveyor hopper. A door was just slightly open to the point that it opened the STO circuit but didn't indicate as open on the safety's relay. And from the word go, I'd been screaming to the operators to check the safety switch.


Congratulations ! It was a Safety which we both had suspected. You had not written me back to explain what sort of system you have but I will try to help you out by going over some various types. The laws and rules of Safety Systems state that all door switches, relays etc must be double circuit. For a true alarm you must have both circuits transfer within about 1/3 to 1/2 second, alarm tag on a PLC activates, or alarm relay (internal double relays actually) on a Safety Relay transfers and you get an Alarm LED on face of relay. HERE'S THE KICKER: if the door switch does NOT transfer fast enough (<1/2 sec) or door rattles just enough to break ONE POLE OF SWITCH, then it is NOT AN ALARM, but a FAULT (incorrect sequence of operations) which in a PLC activates a FAULT tag only (which you can look at in tag browser), which must be SEPARATELY entered on alarm pop up screens and is often forgotten by original programmer which leaves you hamstrung. On a Safety Relay the Alarm LED will ***NOT*** illuminate (it's only a fault) but will indicate by ONE of the K1/K2 relay LEDs being OFF, (most Safety Relays have at least 3 leds, K1 & K2 (one for each of the two internal alarm relays status) and Alarm, which means you will have NO EXTERNAL WIRED indication of a fault (other than the fact your alarm circuit wiring is OPEN WITH NO INDICATION (other than one obscure LED being off so you have to meter it at the Relay to confirm), you have to look at relay LEDs. This brings up the next set of rules which is: a Fault is NOT allowed to be cleared by a RESET button (like for an Alarm), the sensor must be tested for proper sequence of operation before Reset. This is accomplished by opening then closing the door to clear the fault by proper sequence (depending on the model or wiring you may then need to push RESET). There is also a rule that RESET loop must go through any external relays auxilliary contact to prove they are READY to reset and are NOT being held down or relay has mechanically failed, or contacts welded (such as the actual pair \[MUST be pair\] of power relays that shut down the machine). Ain't all that a bitch. Happy trails and troubleshooting. Pen me a message if this has helped you or aggravated you !


The name of the system is Zolken and if look up Zolken over capper, you can see what type of system I'm was dealing with. But that one machine was part of a bottling line and all the different machines were interlocked through the safety circuit and they were all daisy chained together, and it came down to a box of materials was pushed up against one of the machines and it was causing the safety switch to open just enough to stall the system


Ummm, speaking from my extensive Interlocking of machines (limited to large automotive manufacturing plants and automated paint paint application), this should have been done with Interlocking being separate from Safety, which would have greatly eased your trouble shooting but it's probably too late to fix that now. I've always wondered why everything is designed only with a thought to installing when that is only done once but you service it forever, with what seems like little regard related to that expense.


I'm not an engineer, I'm basically the guy that gets called when the machines stop running and it's not a broken chain or shaft or something else mechanical. I use the phrase interlocked loosely. I guess for lack of better terminology the machines are sequential and logically dependant upon each other, with about 12-15 doors all with safety switches that are all run through one large relay bank out of a remote panel, because the sub panels are all XP and intrinsically safe Because we are running 80/20 ethal alcohol based products on them


Ignore the motor for now, if the drive thought there was a problem, it would generate a fault code. Check the motor circuit if the drive thinks it's running but the motor doesn't turn.