Sales | Marshall Wolf Automation

TECO AC Drive Question

Wednesday, May 15, 2013
by Scott Welch

Question:

I have a Teco JNEV-203-H1 variable frequency drive that I just received. When enabled, it will run up and oscillate between 5-6 hertz. After I disable then re-enable and off we go and will run up to speed.

Answer:

This depends on the motor that is being used. We have seen this before with other vendors motors. Because the drive is defaulted in sensorless vector mode and the algorithms are pre-set for TECO motors, the units sometimes get "confused" by other motors in sensorless vector mode.

You should convert from Sensorless Vector to V/f

1. Set parameter F51 to 1 to access C parameters. Then Press the function button to get the C menu.

2. Set C14 = 001, and the problem should disappear.

Marshall Wolf Automation can help you with your variable frequency drive applications!

Tech Question Regarding AC Tech Lenze SMVector Drives

Monday, May 6, 2013
by Scott Welch

Question:

I took your advice and downloaded the operator's manual for the Lenze AC Tech SM vector drive and have read through it a couple of times. I have a couple of concerns:

# 1- I have some worry about the admonition about starting the drive into a coasting motor. In our application it should not be a big problem but there's always a chance that the operator could give a "stop" command, change his/her mind and immediately give a "run" command while the motor was still coasting down.

If I understand the manual, if we set the controller to stop with DC braking, the motor will not restart until it has come to a stop. That is, a "run" command would be ignored until the motor had stopped. Is that a correct interpretation?

#2 - Second, for the motor parameters required for torque limiting in vector torque mode, the stator resistance and stator inductance could be measured directly but the manual seems to suggest that those parameters would also be calculated by the controller during set-up, depending on how P399 is set. Am I interpreting this correctly?

Answers:

#1 The drive will not start if the DC brake is active; but keep in mind, if the drive is set up for coast with a DC brake, the moment the drive sees a stop command the DC brake will engage. So, the motor will have a DC voltage applied and will probably still be spinning, you can do that, but it’s not good for all applications.

#2 As far as the stator resistance and inductance go. Those values are actually measured by the drive during the calibration for vector mode. So typically after entering 306-306, set 399 to standard calibration and apply a start command.

Send your questions in! Marshall Wolf Automation offers in-house technical support for all of our products.

Student Looking For A Variable Frequency Drive Recommendation

Tuesday, April 30, 2013
by Scott Welch

Question:

I am a Ph.D. student working in the Department of Mechanical Engineering in the University of British Columbia.

I have a blower with a 230/460 Volts AC, Three Phase (17.4/8.7 Amps), 7.5 hp motor.

I am looking for a variable frequency drive for this blower to change the motor speed and so blower flow rate.

Please provide me with your suggestions for appropriate VFD for described motor that suit my technical requirements.

I look forward to hearing from you soon.

Answer:

Take a look at the AC Tech SM Vector variable frequency drive. Below I have quoted both the 230 and 460 volt input versions as I did not know the input voltage and the motor can run off either.

ESV552N02TXB AC Tech 7.5 HP Nema 1 230 volt input $441.10 or ESV552N04TXB AC Tech 7.5 HP Nema 1 460 volt input $438.90

Marshall Wolf Automation is your authorized AC Tech Lenze distributor for their complete line of high performance AC drives.Whic

Nardini Lathe Question

Friday, April 26, 2013
by Scott Welch

Question:

Hello, I have a Nardini lathe that uses a 'zero speed' control relay that works in conjunction with an NPN sensor. The machine was made in Brazil and it is difficult to find replacement parts.

Would you have a replacement part of some type I can use? The information I have on the device is as follows.

Dual contact SPDT (4A/250) 50-500 RPM. it is a "Sense model ND-333-30" 220VAC

Our Suggestion:

We offer speed sensors which can be used for certain speed ranges or we also offer a zero speed monitor that can be used with 3 and 4 wire sensors or NAMUR sensors that can give a zero and opposite direction output.

Here is the link.

Marshall Wolf Automation is a large stocking Pepperl+Fuchs distributor.

Tech Question Regarding A Tensioning Application

Friday, April 26, 2013
by Scott Welch

Question:

I'm doing some engineering work for a small company here in North Carolina. The project involves making a textile winder which ideally would maintain constant fabric tension while a spool is filled. Just an FYI, the spool diameter varies from 3.25" diameter to 10.5" diameter. Desired fabric tension is around 5 lbs and the textile speed is around 3' per minute.

In the past, they've used a small DC gearmotor running at constant speed, along with a mechanical a slipper clutch to take care of the speed differential. The system works....sort of, but the tension is never really correct because of the varying diameter and the speed is correct only because of the slipper clutch.

I thought that perhaps we could accomplish the same thing with a 3-phase gear motor under VFD control. We have quite a bit of experience with the ACTech VFD controller and we could control speed using that device's 0-10 Volt signal input along with a sensor to detect how full the spool had become. However, the AC Tech unit does not offer any control parameters which can limit motor torque.

So after all this preamble, my question is, are there other variable frequency drives which do have motor torque control parameters available? The power requirements for this winder are quite low, certainly less than 1/10th horsepower so for almost any conceivable 3 phase motor, the torque limitation would have to be down in the range of, say, 10% to 20% of the full load capability of the motor. Is this feasible or should we stick with the slipper clutch?

I know there are many much more sophisticated winder tension control systems available but almost all of them would be "overkill" for this project.

Answer:

Take a look at the Vector Control Mode on the AC Tech SM Vector series of high performance AC drives. The SMVector does have a parameter that can limit the % torque limit of the motor using P330 or a preset torque set point using P331-333. Keep in mind that these parameters are only active in Vector Torque mode(P300:05). In Vector torque mode the torque is controlled independent of speed. Also, Vector mode does not work correctly if P302/303/304/305/306 are not set according to motor data.

Single Phase Motors; A Common Question

Thursday, April 25, 2013
by Scott Welch

Single phase motors are not controlled by varying the frequency in the same manner of a VFD but are controlled by varying the voltage.

The basic design of the capacitor start motor is to maintain synchronous speed. These motors are built with a centrifugal switch on board.

When the speed of the motor drops below a fixed speed the switch will make contact and fire the capacitor to bring the motor back up to synchronous speed. If you vary the voltage to these motors, the capacitor will keep recharging and trying to get the motor to the synchronous speed until the capacitor fails and the motor itself fails.

The best way to get the variable speed you require would be to replace the motor with a three phase motor and a VFD. The VFD can run off single or three phase power and will give you a three phase output to control the motor speed. We have vendors that offer extended warranty (up to three years) with the purchase of a motor drive package.

Interested in hearing more regarding single phase motor applications? Contact us today!

Do I Need NEMA 4 For This Application?

Saturday, April 20, 2013
by Scott Welch

Question:

Hello, I have a Baldor M3211T motor. It's 3hp, 3 phase ,1725 rpms. I'm looking to put a variable frequency drive on this motor to control the speed of one of my 2" x 72" belt grinders used in my knife making business.

It would need to mount on the grinder frame so it will get quite exposed to grinding dust but not water. Not sure if Nema 4 is absolutely required for this or not.

Also, I would like a potentiometer knob on the drive. Looking to keep it as economical as possible.

Answer:

I cannot find the M3211T on the Baldor site so this may be an older motor. The closest I find is the following:

EM3211T Baldor 3HP,1760RPM,3PH,60HZ,182T,3630M,OPSB,F1

The fine grinds seem to find themselves into just about anything. I would suggest going to a Nema 4 variable frequency drive to help protect the drive from your environment. That being said, Nema 4 drives are sealed up and do not offer potentiometers on the face for this reason. Potentiometers are difficult to seal up.

I need to know what your input voltage/phase you have available to power the drive and I need you to verify this is a 3 hp 230 volt three phase input motor and I can give you a few options.

Do you need help on your application? Send it over and we'll get right back to you. Marshall Wolf Automation has a complete offering of high performance AC drives, industrial electric motors and all the automation components you need!

I Don't Want To Overheat...

Thursday, March 28, 2013
by Scott Welch

Question:

I got everything working, and the Stretch Wrap machine has come back to life.

Everything worked perfect!! I have one question on the variable frequency drives, everything is in a 16x12x4 box. I have the drives set up to turn the drive fans on when running. I also see a setting to have the fans come on with a preset temp.

I tried this and they just don’t seem to be coming on. The box does get warm and I don’t want to have a problem with overheating anything.

Do you know what the preset temp is and would this be the way to set it up or would I be better off just having the fans run when the drives are working?

Answer:

My sources tell me that there is a temperature sensor somewhere on the output transistor, and when it reaches 50 Deg C, the fan will kick on.

Please note that this temperature is measured at the IGBT around the heat sink, so the enclosure may feel warm, and lag a little in cooling off once the fan kicks in.

Baldor and The Movable Platform

Thursday, March 28, 2013
by Scott Welch

Question:

We would like options to use 110 volts and we try to avoid 220 or 240 volts because 220 volt outlet is 50 feet away from platform that is movable with 10 straight wheel casters.

Platform will be real heavy as it will need to hold 4 people and a huge bed.

Brand : Baldor
MAX INPUT:.471
Ratio 40
Output torque .1
461 in. lbs
ID#HF-918-40-BS or B5-H100
Cat. Spec GHF4018AH/GRO212B006
Serial#G24000153

Answer:

GH1/54C Teco Westinghouse 1.5 hp 230/460 three phase induction motor 56c frame with feet $213.60

ESV112N01SXB AC Tech 115 volt single phase input, 230 volt three phase output rated at 1.5 hp output - variable frequency drive

The gearbox you currently have will only take in .47 hp and will not stand up to a 1.5 hp motor.

I looked at Baldor and did not see a 40:1 ratio available at 1.5 hp. You have a little room on the gear ratio as the drive will help with the actual output speed but at 461 in lbs of torque that you are currently attaining, which is not nearly enough torque to do what you want.

A 1.5 horse power motor with a 40:1 would give you roughly 2160 in lbs. A 30:1 would get you to 1620 in lbs.

You can verify your torque needs by connect a torque wrench at the point where you couple to the platform. Load it up and give it several pulls and document the torque necessary to get the platform to move with a full load. This will get you in the ball park torque wise and then we will know what the best gear ratio for the application.

The drive will maintain torque through the speed range but will not increase the torque developed by the motor/gearbox combination.

Scott Welch, Technical Sales Support

Do you have a technical question we can help with? Ask Tech Support!

Please Recommend An AC Tech Lenze AC Drive For My Application

Friday, March 22, 2013
by Scott Welch

Question:

Last week you were most helpful with a selection of a variable frequency drive. I received the drive yesterday & will be installing it soon.

That said, I had an issue develop with another existing drive this morning & I would like to replace it. It controls a motor to a larger process blower, so it will have slightly different specifications (10 HP/ 7.5 kW, 480 VAC, three phase input & output).

I would also like it with a NEMA 4x enclosure. Another of the AC Tech/ Lenze brands would be fine. Could you help me with the configuration?

Answer:

This high performance AC drive should handle this new application.

ESV752N04TXD AC Tech Nema 4X, 10 hp, 480 volt, three phase in and out. - $790.90

Can I help you with a drive application? Marshall Wolf Automation has a large inventory of variable frequency drives readily available and in-house tech support too!