Overvoltage fault.

[Jraef]

P6.18 Braking Voltage Level
230V series - 370.0V to 450.0V Default = 380.0
460V series - 740.0V to 900.0V Default = 760.0

As to the bus regulation, it says to disable that if using the braking resistors. P6.05 = 01 to DISable.

It doesn't say what the OV trip level threshold is unfortunately. But the input voltage tolerance is +10% of 480V, so that's 528V max, which would put the DC bus at approx. 745V. So obviously the drive can take more than that because the brake threshold is set for 760V. I would leave it at the default.

As I read it, the 10HP drive that you have already has the brake transistor built-in, all you need is the resistor, not the entire braking unit. It looks as though the jumper you referred to might be associated with the braking UNIT. For your drive, you would just use P6.18 to program the threshold of where it turns on, but like I said, I would leave it at the default. All you will need is a 75ohm resistor, rated for at least 1000W (from the manual). More wattage is better for lasting longer but you MUST retain the resistance at 75ohm minimum, that's critical so that you don't smoke the transistor in the drive. The resistors are going to get very hot, so think about that when locating them, especially in terms of someone possibly touching them.

 

[ptonsparky]

P6.18 Braking Voltage Level
230V series - 370.0V to 450.0V Default = 380.0
460V series - 740.0V to 900.0V Default = 760.0

As to the bus regulation, it says to disable that if using the braking resistors. P6.05 = 01 to DISable.

It doesn't say what the OV trip level threshold is unfortunately. But the input voltage tolerance is +10% of 480V, so that's 528V max, which would put the DC bus at approx. 745V. So obviously the drive can take more than that because the brake threshold is set for 760V. I would leave it at the default.

As I read it, the 10HP drive that you have already has the brake transistor built-in, all you need is the resistor, not the entire braking unit. It looks as though the jumper you referred to might be associated with the braking UNIT. For your drive, you would just use P6.18 to program the threshold of where it turns on, but like I said, I would leave it at the default. All you will need is a 75ohm resistor, rated for at least 1000W (from the manual). More wattage is better for lasting longer but you MUST retain the resistance at 75ohm minimum, that's critical so that you don't smoke the transistor in the drive. The resistors are going to get very hot, so think about that when locating them, especially in terms of someone possibly touching them.

We were using 480 in our math this afternoon. The extra 10% helps in understanding their 760 volt threshold.

We priced them a complete exam of the starters, clean the old AB aux contacts, and disconnect an old motor starter that has no motor load but is still in the interlock circuit. That and a few measurements with the resurrected laptop and Fluke 43B.

I think the sewing machine control will be modified with a timer to keep it locked in for the first second. After that it works fine.

The resistor will be if all else fails. There is not a good place for one in the area that has product dust in the air at times.

thank you.

 

[ptonsparky]

Beating the horse..

Beating the horse..

They get another taillight warranty. Basically the micro switch was out of adjustment, again. Locknuts were loose. Made the adjustments. Again, told them it would last until whenever. We suggested the timer solution, but no sale. We can go back.

We did replace an interlock contact and a fork terminal that wasn't crimped properly.

 

[Cow]

They get another taillight warranty. Basically the micro switch was out of adjustment, again. Locknuts were loose. Made the adjustments. Again, told them it would last until whenever. We suggested the timer solution, but no sale. We can go back.

We did replace an interlock contact and a fork terminal that wasn't crimped properly.

Trust me, you're not the only one with customers that like to learn the hard way several times before doing it the right way. I'm on a project right now that's basically a do over, our contract is around $350k and climbing every day with changes. The customer tells me, not to worry, it's job security...:blink:

 

[Sahib]

I think the sewing machine control will be modified with a timer to keep it locked in for the first second. After that it works fine.



.

It is not clear how you could do that. My alternative suggestion is this. The chattering is due to low voltage (but not too low enough to drop out contactor). Anyway, putting a voltage regulator might solve your problem.

 

[ptonsparky]

It is not clear how you could do that. My alternative suggestion is this. The chattering is due to low voltage (but not too low enough to drop out contactor). Anyway, putting a voltage regulator might solve your problem.

One thing we do not have is low voltage.

 

[ptonsparky]

Crude drawing, but this is how. Micro switch is erratic at start. On to Off is about the thickness of a postcard at this point. Belt must be on, then M pulls in and TMR starts in, after Micro makes. TMR contact opens approx 1 sec later giving control back to MS. It is stable by then.
View attachment 16962

 

[Sahib]

One thing we do not have is low voltage.

To be sure, what is the voltage across contactor coil, while chattering happens?

 

[ptonsparky]

To be sure, what is the voltage across contactor coil, while chattering happens?

Well, my SEWAG is that it rapidly cycles from 120,0,120,0, etc. as the limit switch, closes, opens, closes, etc. Rapidly.

Well, hey, you are right...the voltage drops to zero.

 

[ptonsparky]

The largest motor on sight is a 480v 100 hp across the line start hammer mill. We hear the wires vibrating in the conduit but the lights don't flicker. No Low Voltage.

 

[Sahib]

Well, my SEWAG is that it rapidly cycles from 120,0,120,0, etc. as the limit switch, closes, opens, closes, etc. Rapidly.

.

Are you saying voltage change at contactor coil is too rapid for a voltage regulator to change the voltage profile?

 

[ptonsparky]

Are you saying voltage change at contactor coil is too rapid for a voltage regulator to change the voltage profile?

Are you saying that voltage regulator will prevent the open switch from dropping out the coil voltage?

 

[Sahib]

Well, the starter contactor on and off in line with ms operation. Correct? In that case if the cycle time is greater than voltage correction time of a servo voltage regulator, then it may be possible to improve voltage across coil and prevent chattering.

 

[kwired]

Well, the starter contactor on and off in line with ms operation. Correct? In that case if the cycle time is greater than voltage correction time of a servo voltage regulator, then it may be possible to improve voltage across coil and prevent chattering.

I think he has an unstable switch that is opening/closing rapidly for some reason causing rapid cycle of the motor contactor. More of a mechanical issue then an electrical issue from what I understand.

 

[ptonsparky]

I think he has an unstable switch that is opening/closing rapidly for some reason causing rapid cycle of the motor contactor. More of a mechanical issue then an electrical issue from what I understand.

I thought that was what I was saying...

 

[Sahib]

Even after replacing the switch, the issue persists per OP. So I think a voltage regulator might help solve the issue.......

 

[ptonsparky]

Went back with a more accurate TDR than the dial one I had there. 1.24 seconds seems to be the magic # to bypass the touchy micro switch. I also put a surge suppressor on the starter coil for good measure. Bus Voltage never peaked over 726 for the time I recorded. Purring like a pussy cat, as my Dad would have said. We will see.

 

[kwired]

Even after replacing the switch, the issue persists per OP. So I think a voltage regulator might help solve the issue.......

Or find out why the switch cycles too rapidly and solve that issue.

 

[Sahib]

Or find out why the switch cycles too rapidly and solve that issue.

Has the OP given enough input for that?

 

[ptonsparky]

Or find out why the switch cycles too rapidly and solve that issue.

The newer machines use a photo eye instead. Suppose there is a link to history? Like I said before, until the last VFD, it didn't matter.

I did talk to tech support for the VFD. Very quick and very good although when asked just how much I could turn up the 780 volt limit on the DC bus he used the techy term of "a bit". He really liked the idea of the braking resistor and immediately followed with the additional parameter changes. I did not let him know that was not my idea.:angel: