Setting up instantaneous breaker and thermal overload for drag motor..

[cpickett]

Yes I agree on the overload. that way your motor and conductors stay protected... by uncouple do you mean take the belts off and see if I can get the it breaker to hold at the lower value, or see if it trips instantly as well?

Correct, if there are belts instead of a chain or coupling, that would be really easy to isolate your issue to the motor itself or purely mechanical. Depending on how the belts are tensioned you could just release tension and let the belts slip. You shouldn't need to run the motor long with the belts loose to determine if your motor is the issue. Of course if the belts are on the output side of a gearbox you would still not be sure if it's the motor or the gearbox. Just keep isolating sections until you find the issue.

I know you said you are not mechanically minded but unfortunately troubleshooting mechanical issues are probably 50% of a controls guy's job. You have to be able to determine if the issue really is electrical or not, and if it's not you have to be able to convince everyone that it isn't electrical, which is always an uphill battle. You seem like you are willing and eager to learn so keep with it and you'll get it. The good part about having issues is that it will give you more experience for troubleshooting the next job...

 

[ctaylo360860]

Correct, if there are belts instead of a chain or coupling, that would be really easy to isolate your issue to the motor itself or purely mechanical. Depending on how the belts are tensioned you could just release tension and let the belts slip. You shouldn't need to run the motor long with the belts loose to determine if your motor is the issue. Of course if the belts are on the output side of a gearbox you would still not be sure if it's the motor or the gearbox. Just keep isolating sections until you find the issue.

I know you said you are not mechanically minded but unfortunately troubleshooting mechanical issues are probably 50% of a controls guy's job. You have to be able to determine if the issue really is electrical or not, and if it's not you have to be able to convince everyone that it isn't electrical, which is always an uphill battle. You seem like you are willing and eager to learn so keep with it and you'll get it. The good part about having issues is that it will give you more experience for troubleshooting the next job...

I have some guys that work for the company that are smarter about the mechanical side of it so I'll cuss and discuss with them on how easy it will be to get the motor isolated from the gear box. I'm still learning that's for sure, but yes like you said willing and eager to learn. Yeah they already keep telling me to turn it up like the other side, which I'm not willing to do. what is you opinion on using the calues givin in 430.250 vs the nameplate?

 

[cpickett]

Someone with more code knowledge than me should correct me if I'm wrong, but my understanding is you use the table values to size your breaker and wire, because they are worst case (higher) than most motors, but then you use the nameplate values to set the overloads and inst. setting. For the instantaneous setting we are probably splitting hairs on using the table values vs. the nameplate, so if I was in your spot and all else fails I'd probably set it where it works...

However, IMO it's worth investigating because a typical induction motor should use 5-7x FLA on startup, and you are getting trips with the breaker set 13-14x FLA. Usually the fix for this would be a soft start or VFD but 40HP is not that big of a motor to start across-the-line if you don't need speed control.

And you are right to keep investigating this because if you are having this problem unloaded and the conveyor trips out or is stopped fully loaded you may not get it started at all.

 

[ctaylo360860]

So I found some of the problem I was looking at the wrong motor nameplate! The picture I posted is of a 40hp aeration fan... 48x13 is 624. When I set the breaker at 631 it ran majority of the time, but I still had a few trips for some reason.... they’re now wanting to run corn through it. they have to start the drag motorfirst before starting the leg so as long as it turns on and doesn’t trip the it breaker it should hold once product starts going through it....

 

[Russs57]

Let's be clear. Is the breaker tripping only when the motor is starting....or it tripping sometimes when the motor is already running?

I'd be wondering if there is some insulation fault between breaker and motor soft start. Maybe something that needs the right vibration/wind/whatever to rear it's ugly head.

I also wouldn't discount the possibility of a brand new breaker being bad.

 

[ctaylo360860]

Let's be clear. Is the breaker tripping only when the motor is starting....or it tripping sometimes when the motor is already running?

I'd be wondering if there is some insulation fault between breaker and motor soft start. Maybe something that needs the right vibration/wind/whatever to rear it's ugly head.

I also wouldn't discount the possibility of a brand new breaker being bad.

its only on start up so i believe its in-rush- Schnieder electric sales rep says these new high energy efficient motor thats pulling more in rush on start up... everything isbrand new and shouldn't be a problem, but lie you said i wouldn't place it out of the question. I also have a aeration fan motor that will trip the instant breaker at 528amps and the motor load is 45 on the name plate so that is about 100% if i turned it up to the next value of 631 it holds. I know this is over the 1300%, but i don't know what else to do because the only thing that could cause a load on the motor would be a negative pressure in the fan tube.... im currently checking with baldor to see what the inrush on this particular motor should be...

 

[ptonsparky]

Look back at post 14. He explains that the IT setting of the breaker has nothing to do with the load on the motor.

Belts are a different a animal than augers, obviously.
That belt is certainly started before corn hits it. Please tell me yes.

 

[ctaylo360860]

Look back at post 14. He explains that the IT setting of the breaker has nothing to do with the load on the motor.

Belts are a different a animal than augers, obviously.
That belt is certainly started before corn hits it. Please tell me yes.

yes sir the drag motor/ belt is in an entirely different motor control center so in theory they should start up the drag motor and let it get to full speed before they walk about 50 ft to another mcc, and start leg motor which should run it up to the top and distribute it to the drag and fill the back bin up...

 

[ptonsparky]

Starting to sound like a design issue.

Those big aeration fans take forever to get moving but again as explained back in post 14, that shouldn’t matter.

Turn the settings up until they start consistently, make sure the overloads are set at the nameplate value of the motor. Not NEC table values.

One of the problems we come across often enough is that the augers and legs are run consistently into the SFA. Design was 20000 BPH but operators want 24000.

 

[ptonsparky]

yes sir the drag motor/ belt is in an entirely different motor control center so in theory they should start up the drag motor and let it get to full speed before they walk about 50 ft to another mcc, and start leg motor which should run it up to the top and distribute it to the drag and fill the back bin up...

Are you saying there is no interlock between the leg and the belt?

 

[ctaylo360860]

Are you saying there is no interlock between the leg and the belt?

Yeah that could very well be I have never seen a set of prints for anything being built here... There is no interlock between the leg and drag that im aware of... there are some definite flaws in the way this system was designed and or built... I wired the new 500,000 bushel bin but the leg and the other three bins were existing. I believe the maxitronic will shut the leg down if starts to pull to much amperage, or it will adjust the speed of the motor as its on a soft start.... still new pretty new to motor control, and or grain systems.... I'm trying to do my best, to clean things up and actually have them up to code, but i'm only one man...

 

[ctaylo360860]

General Characteristics

Full Load Torque 0 LB-FT

No-Load Current 0 A

Line-Line Res. @ 25° C 0.139 Ohms A Ph / 0 Ohms B Ph

Temp. Rise @ Rated Load 54° C

Temp. Rise @ S.F. Load 66° C

Start Configuration DOL

Break-Down Torque 396 LB-FT

Pull-Up Torque 198 LB-FT

Locked-Rotor Torque 222 LB-FT

Starting Current 347 A
here are the performance specs that I found from the manufacturer.....

 

[ctaylo360860]

heres a link to the motor for more of the motor specs from baldor. https://www.baldor.com/catalog/FDEM4110T#tab="specs"

 

[ctaylo360860]

Are you saying there is no interlock between the leg and the belt?

I looked up the starting current of the motor and it’s only 347amps do you think that the 40hp motor is undersized and not big enough to get everything moving on start up?

 

[ptonsparky]

I looked up the starting current of the motor and it’s only 347amps do you think that the 40hp motor is undersized and not big enough to get everything moving on start up?

I can’t tell you that. The company selling that drag would know what is required. Have you measured the start amperage?
My preference would be the drag starts empty and is empty before it is stopped. The leg usually runs continually. We monitor the belt speed of the leg. Typically a 5% reduction would stop the source to the leg allowing it to clear. 10% would stop the leg because something is slipping. We would have monitored the drag speed using the same parameters, stopping the leg source first. You need some interlocking to help prevent a full scale failure. IMO,Relying on overloads and breakers Is asking for trouble.

 

[ctaylo360860]

My meter won’t show a reading, but I have tried... I agree with you totally! The only thing is the leg needs to run at times when the drag isn’t to fill different bins, so I’m not sure how I could interlock them? The design is a mess I believe they should of built the leg higher and in a different location so they could use the distributor to fill the bins and eliminste the top drags....

 

[ptonsparky]

My meter won’t show a reading, but I have tried... I agree with you totally! The only thing is the leg needs to run at times when the drag isn’t to fill different bins, so I’m not sure how I could interlock them? The design is a mess I believe they should of built the leg higher and in a different location so they could use the distributor to fill the bins and eliminste the top drags....

Select destination Bin 1. Needed interlocks are included. Those items not needed are excluded.
Repeat for each destination.

We use small PLCs. One input can be used in any number of situations as needed.

 

[ATSman]

I don't know if any of this info applies to the OP but it might help others doing startup and commissioning on larger systems.
Years ago I did startup on MV soft starters for multiple conveyor systems to move product from a refinery to a barge to be shipped overseas.
The starters were made by Benshaw and it took quite a while checking the controller settings: Ramp Time, Kick Current, Kick Time, Stall Time, etc.
CT ratios, motor FLA, rigorous testing, etc, before we were able to get the motors from tripping out when moving product and sort every thing out.