Dc motors and drives

[quebmaint]

Hi all here's a nonplc question but I need help. I have a 5hp dc motor and a basic minarak drive I'm on what is looking like my next drive I can't figure out what's going on I'm using a 4-20ma signal to speed the motor up the drive and motor will turn on and run for 5 minutes then it blows L1&2 fuses signal phase to drive. It blows the 50amp fuses but the drive 30fuses are fine. We sent the motor out and vendor says its fine what could it possibly be a thoughts. Please help I'm at my witts end

 

[milldrone]

I'm using a 4-20ma signal to speed the motor up the drive and motor will turn on and run for 5 minutes then it blows L1&2 fuses signal phase to drive. It blows the 50amp fuses but the drive 30fuses are fine.

Questions:

1. Is this speed that you mention a speed that you have been able to run before?

2. You mentioned "L1&2", Is this a three phase input drive or a single phase input drive?

3. Have you monitored the amps on the 50 amp fuses during one of these events?
3a. Have you monitored the amps on the 30 amp fuses during one of these events?

4. Have you tried the drive without a motor connected?
4a. Have you tried the drive with only the field connected?

5. Have you checked the field current and or voltage against the motor name plate values?

6.Have you monitored the armature current and or voltage?

 

[leitmotif]

Do you have a correct match between motor and drive. What type of motor? What is load motor is driving - could load be overloading motor and drive - as stated check line amps voltage and motor RPM.

Please provide better description of the 30 and 50 amp fuses and where they are in the circuitry.

Dan Bentler

 

[quebmaint]

The 50amp fuse comes from start up contactor and feeds the 30ampL1L2 fuses to the drive. No I did not check amperage on these as u wasn't expecting it to go out on me. I had the motor running with and with out a load because with a load it looked like the belts were slipping on the conv. So I took the motor off to see if the surging was the motor or conv and motor ran smooth then the fuses blew

 

[quebmaint]

Questions:

1. Is this speed that you mention a speed that you have been able to run before? Yes

2. You mentioned "L1&2", Is this a three phase input drive or a single phase input drive?Single phase

3. Have you monitored the amps on the 50 amp fuses during one of these events?no it seems to be one shot then the drive is done the first time it happened I thought it was an error on my part but this time I'm not sure I verified the jumpers were in the right spot
3a. Have you monitored the amps on the 30 amp fuses during one of these events?

4. Have you tried the drive without a motor connected?no I have always thought a load was needed
4a. Have you tried the drive with only the field connected?

5. Have you checked the field current and or voltage against the motor name plate values?

6.Have you monitored the armature current and or voltage?

1 yes.
2 single phase if you read the quote I answered 3 as for the rest of them no same as 3

 

[milldrone]

3. Have you monitored the amps on the 50 amp fuses during one of these events?

no it seems to be one shot then the drive is done the first time it happened

1. Does this mean you believe the first drive is now defective?

2. Do you have the model number for the drive?

3. Some DC motors will have a ohm value for the field on the tag, if your motor does, how does it compare to the actual value? If it does not, does it have a voltage and amp value?

4. How many field leads does your motor have?

 

[quebmaint]

1. Does this mean you believe the first drive is now defective?

2. Do you have the model number for the drive?

3. Some DC motors will have a ohm value for the field on the tag, if your motor does, how does it compare to the actual value? If it does not, does it have a voltage and amp value?

4. How many field leads does your motor have?

1 yes I believe so

2 I believe minarak rg 5500u I'm not positive I'm not at work at the moment
3 it has amperage and voltage not sure about ohm
4 no field just arm
5 also uses regen breaks
You think it's possible the vendor was wrong about the motor?

 

[milldrone]

4 no field just arm

So you are saying just two wires from the motor?

 

[quebmaint]

Yes just two leads that's why I can't believe I'm having this much trouble. This something I have done many of times

 

[DickDV]

If the single phase supply voltage is 120VAC then the motor armature voltage must be 90VDC. If the supply is 240VAC single phase, then the armature voltage must be 180VDC.

Check that out. You may have the wrong armature voltage for the supply you are using.

 

[quebmaint]

I have the jumpers set to 240 vac and 180 vdc arm voltage

 

[OkiePC]

Odd website.

Unable to post hyperlink to the drive manual but you can get to it easiest by going to DC Drives, Parametric Search, then put in 5HP and only two pop up.

If you register with them a manual can be downloaded. If you attempt to register with them you will see some funny error messages, but if you hit the 'having trouble' link you get a window with what is allegedly loading up the manual...still waiting...

EDIT: Impatience got the better of me, so I copied the text RG5500u.pdf, right click, Search Google, and found some-other-body's copy of it:

http://www.alstron.com.sg/PDF/Minarik/250-0225-RG5500U.pdf

Attaching a pdf of the overview page (had to print to Cute pdf)...

 

[leitmotif]

I can see it starting right now. 20 questions and pulling hens teeth.

Please supply the following info
1. Line phases and voltage
2. Nameplate on drive or adequate description of rated line voltage and current. Rated motor type volts and amps
3. Nameplate info on motor OR type of motor as I asked for in #3. Include rated voltage and current, HP and RPM. Sure would be nice to include rated torque
4. Take torque wrench and measure torque at the input of the conveyer ideally the gearbox input shaft.

Dan Bentler

 

[quebmaint]

Yes that's the one any suggestions?

 

[Lancie1]

The 50 amp fuse comes from the start-up contactor and feeds the 30amp L1 & L2 fuses to the drive.

...(5) also uses regen breaks

Do the 50-Amp fuses feed anything else? In other words, why did someone use another set of 50-amp fuses, when 30 would do for the drive? Do the 50-amp fuses feed the regenerative brake also? If the 50 Amp fuses feed something else, the high-resistance fault could be there instead of in the drive. Check EVERYTHING (devices, wires, ternminals, connectors) downstream of the 50-Amp fuses. Look for burned spots, discoloration, melted insulation, cut or worn insulation, wire "whiskers" that are partially bridging two terminals, and shorted-out coil or resistor in the brake.