Flux Vector Control 2

[marshg]

I have configured a flux vector control drive to run a belt conveyor that moves a 40lbs load using a 1hp motor. The motor is designed for this type of drive.


Here's the problem:
Our customer was running the conveyor at 300rpm and it was running fine for a while. Now it stops and then starts back up on its own. This tells me that that the motor is starting to overheat, which our customer had complained that the motor was getting hot.

1) I had him increase the speed up to about 600rpm (rated is 1750) and see if the problem went away, which would have told me there would of been a problem with the fan. It didn't go away. BTW, We are going down to the site on Wednesday to investigate further.

2) I called up tech support to ask them what the problem could be.
- They informed me that the motor may not have enough torque at that speed to run the conveyor at that speed. Btw, the belt was tight and our customer loosened it up w/out success.
- Tech support also said the motor may be overworked too.
- I asked him if I could have caused any of these problems by the parameters I programmed into the drive. He told me the only parameters to check were the rated voltage and current, which I did. I am unsure of this because my customer is in contact w/ another tech guy from the same company and he says that the problem is the way I tuned the drive.

What I really need to know for sure is if there is anyway that I could have messed up with one or many of the parameters that I configured (i.e. mag amps, current integral or proportion gain, stator resistance, etc.) that would be giving us this problem??

Thanks in advance. If anyone needs more of an explanation, let me know and I can send you a phone number to get in contact with me. Thanks!

 

[jbartos]

Suggestion: It is better to follow the drive instruction manual and if in doubt, check with the drive tech support.
There are many websites dealing with the Flux Vector Control, e.g.

http://www.nwmotionproducts.com/id14.html

http://www.advance-technical-sales.com/downloads/drivecon/application_notes/appnote4.pdf

etc. for more info

 

[RadarRay]

If you followed the manual and used the actual data it would be hard to believe you did it incorrectly. But then you should know if you followed it.

I am surprized you didn't say you auto-tuned it. Was auto-tuning available?

Lastly, didn't you record the current/torque it was running 1) just after you set it up 2) when it was running product.

Did you supply a motor that had a vector rating? Probably had 1000:1 Speed ratio, if so, and it wasn't overloaded, it should have not been a problem.

BTW, I wouldn't follow generic instructions. The variety of drives out there seem to be just different enough that you should follow the DRIVE MFG's instructions.

 

[marshg]

I did follow directions of the drive manual.

I ran into a problem with an 'overspeed fault' till I figured out that I was setting my rated speed to my maximum speed. This does not have anything to do with my problem that I wrote about earlier, however, I did reset settings back to the factory presets. I had to program everything over again.

I was wondering if I had missed a step or accidently auto tuned w/ a load on. I will not know the parameter settings till Wednesday and I wanted to be prepared. I looked through my note book and noticed that our customer said that the mag amps (no load current) was 1.89A. The nameplate value is 0.92A. I don't know if this would have caused a problem with the motor voltage.

Also, I had left one of the manuals with our customer who is not at familiar with drives. He was calling me up and asking me if certain parameter should be a certain value or if the calc presets should be set to yes. From the way he was talking, I assume he got ahold of a tech support person and may have tried to fix something on his own. I don't know that for sure so I can't assume that either.

Auto tuning was available, but I didn't use it because the motor was already connected to the load. I followed the directions and made calculations as the manual said in the manual. This wednesday, I will have them disconnect the motor to eliminate the possiblity. Btw, this conveyor does not need to have quick response to error so why do I have to have some of these parameters set (also this motor does not have an encoder)?

I did not record the current/torque of the drive, but will make sure I do this on wed.

The motor was supplied by the manufacturer of the conveyor. I have called up to verify did have a vector rating.

Thanks for your help!

 

[Baldor]

>>...mag amps (no load current) was 1.89A. The nameplate value is 0.92A....<<

That means almost twice the magnetizing current needed. You may have an over-saturated rotor. I sugest you run the (unloaded) motor open loop, measure the current, and enter that value as your mag amps.

 

[Farkel]

OK who's motor, and who's drive are we talking about, plus what type of sheaving or gearing do you have on the conveyor, and what type of belt conveyor, rubber belt, ?, and how long, and what does the fpm at 300rpm represent. Looks like you got about .17HP of power available.

 

[jbartos]

Suggestion to the original posting: Please, would you post nameplate data of the equipment involved?

 

[marshg]

jbartos - Here is the nameplate data:

http://www.baldor.com/products/spec...ct=AC+Motors&family=Vector|vw_ACMotors_Vector

farkel - The motor and drive is from baldor. BTW, there is no fan because it's a TENV type motor. It's been a while since i've worked on this project. Anyway, the conveyor is 9ft. The fpm at 300rpm should be 62.5fpm. Where did you get .17HP? The belt is pretty tight (although I can't say how much of a load it is) and .17hp doesn't sound like enough power to pull it. I hope this didn't damage the motor. It's hard to say how many times our customer ran it, because he had to do some testing to make sure the belt would stay on straight before shipping to the end user.

 

[jbartos]

Question to the previous posting: Which motor drive have you applied to the &quot;vector&quot; motor? Do you have nameplate data for it that you might post?

 

[marshg]

Here's the link:

http://www.baldor.com/products/spec...C+Controls&family=Vector|vw_ACControls_Vector

 

[VicP]

How fast will the motor be running at the maximum conveyoy speed? If the motor never runs faster than 500-600 RPM, the gearing between the motor and the conveyor is incorrect. The motor will produce its rated HP (1) at its rated RPM (1750). At 300 RPM the motor will produce 300/1750 x 1 = .17 HP. If the motor is always running at low RPM, it is probably overloaded. Change the sheave sizes to get the motor to run near its rated speed.

 

[marshg]

This is a vector drive and motor. I didn't size either one. I was just asked to configure it. Nontheless, isn't the vector drive allowed to run the motor at the slower rpm w/out causing problems. Don't forget that our customer told us that the magnetizing amps was 1.89A. This should of been .92 (I don't know how it got up to 1.89). I'm worried that this maybe giving us problems (as well as possibly your suggestion of the motor might be overloaded too). I will find out for sure tomorrow morning when I go to the job site.

 

[Farkel]

First the motor with a vector drive, would produce 3 foot pds of torque constantly throughout it's speed range, and Hp=Torque(ft/pds)xSpeed RPM/5250; so 3x300/5250=.17HP. Secondly, if the conveyor is on a flat surface area HP required would equal Weight of load, plus weight of rollers in belting in pds times friction of type of rollers, say steel sliders would est. at .21 on rubber canvas belting times 62.5 feet per minute divided by 33000 times overall efficiency of drive system.

 

[marshg]

I went to the customer site today and decoupled the motor.
- Before I auto tuned the drive, I ran the motor and the NL current = 1.4A.
- After I auto tuned the motor and ran the motor. The NL current = 1.4A. I then coupled the motor and the motor was pulling 5A! Motor FLA = 3.2A. I called tech support and he told me that the motor was putting out around 5 ft/lbs meaning the motor is undersized. He then told me to decouple the motor and take a torque wrench to see how many ft/lbs. it took to move the conveyor. It took 5.5 ft/lbs. We concluded that the motor was undersized. This raised some questions after talking to a co-worker about this after I'd left.
-> The motor drives a pulley. There are 2 wheel which looked like they were different sizes (I don't know the ratio). The bigger wheel is located at the conveyor and the smaller wheel is at the motor. We measured the torque at the bigger wheel. BTW, this conveyor is used to test baby stollers, so the load has wheels and is hardly pulling any current.

1. Don't gear and belt reducers increase the amount of torque by a ratio?
- If so, and lets say there is a hypothetical 3:1 ration. The torque that the motor would have to put out would be sufficient and the motor would not be undersized. What else would cause the motor to pull 5A?

2. Did I measure the torque correctly if these wheels are
2 different sizes?


btw, I made a mistake when I listed 0.92A for the magnetizing current on previous posts. This value is for the 460V motors, not 230V. The nameplate listing is 1.84.

Thanks for the help!

 

[jbartos]

Suggestion: Visit

http://www.electricmotorsale.com/baldor-ac.html

and notice that Baldor recommends for the conveyors:
Baldor Brake Motors
Baldor's line of brake motors are available in open drip proof, totally enclosed fan cooled, or explosion proof designs, in either single or three phase. Available in stock ratings from .25 horsepower through 30 horsepower. These motors use a mechanical spring set brake with a manual release. Brake motors may be used on conveyors, machine tools, hoists, door operators, speed reducers, or any application requiring quick stops and positive holds. Call (510)490-2187 for additional details and to order. Special sale on now!

The attractive features are a quick stop and positive hold.

The vector motors are recommended as:
Baldor Vector
Vector Drive Baldor Motors are stocked in either totally enclosed blower cooled with an attached constant velocity fan or totally enclosed non-ventilated construction. All motors are supplied with a 1024 line count encoder. Available from 1 through 500 HP in NEMA frame sizes from 56C through 5009L. The motors are ideal in industrial applications where full torque is required from base speed down to zero speed. Applications include test stands, printing presses, material handling, packaging equipment, and others requiring exact speeds and positioning. Call (510)490-2187 for additional details and to order. Special sale on now!

Stressed are: The exact speed and positioning.

It appears that improper motor and drive might be applied to the conveyor.

 

[marshg]

jbardos - My company did not size the motor or drive. We were asked to configure it and make it run. We were hired by fabricator that hired a conveyor company to design the conveyor. The conveyor company then called up baldor and asked them what drive and motor we needed for the mech. specs. and the application itself.

I agree w/ you on this: The conveyor needed to be an approxiamate speed. It was not that vital if the conveyour was commanded to run 500rpm and was only running 490rpm.
What about this: The application did need to run from 100RPM to 4000RPM and all I needed to do was to display the spd of the conveyor. The motor is an encoderless vector. I have only worked with the v/hz drives. I'm not that familiar about determining what motors go w/ a certain apps and would like to learn. What would you suggest for this?

 

[jbartos]

Suggestion: Normally, the manufacturer's sales representatives may visit you and bring you various application notes. They can focus on your specific needs.

 

[Farkel]

What is the model of the Baldor motor, which you have? And what did you determine for the pulley sizes? Your motor may have some bad iron in the stack due to heating, which Baldor may wish to warranty if in parameters. Jabartos may want to do this.

 

[marshg]

I have not heard about the size of the pulleys. Basically, the ball is back in the fabricator's court. Our tech support told us to try measuring the torque w/ a wrench and if it was pulling 5 ft/lbs. of torque, that we may consider going with a bigger motor. Since *we* did not buy and therefore take responsibility for the motor, it will be up to our customer to notify their contacts. If their contacts determine that torque we measured was incorrect, then we will have to contact baldor about the bad iron.

 

[jbartos]

Suggestion: The Baldor Vector Drive Spec reads Input Voltage/Hertz .....50/60
on

http://www.baldor.com/products/spec...C+Controls&family=Vector|vw_ACControls_Vector

It appears that the input voltage is missing.
The conveyor mechanical load characteristic should be verified, whether of not 1HP motor is the correct size.
The original posting indicates that the motor is designed for this kind of drive. There is no statement reading that the motor is designed for this kind of conveyor load application.