7 replies to this topic

[subhash]

Dear Sir
we are using ABB make 200 kw two no drive for 325 kw motor , This motor is connected to Refrigeration Compressor in our HVAC system , Inlast week we face a problem of voltage fluctuation in our plant due to some problem in supply grid , We observe that this drive display is in off condition after voltage dip , we checked drive observe following abnormalites
1.Starting resistor burn completely of both drive
2.Input module ( Thyristor 3.00 nos burn)
3.IGBT 3.00 Nos open
4.NINT -43 Card burn
5.NGDR card burn - 2.00 nos
Sir this happen even when my motor was in off condition only power to drive was on
so please guide us that what protection we should provide to prevent such failure and why this is happen
as we had provided 700 A sf fuse at individual circuit of drive , out of which we observe 3.00 nos fuse blowen
What is drive itself having protection for over come this problem.
Regards
Subhash

[marke]

Hello subhash

Drives and soft starters are most vulnerable to voltage surges and transients when they are connected to the supply, but no current is being drawn. i.e. the motor is not running.
In the case that you describe, it is almost certain that in addition to the power dip, there was a voltage surge. This is commonly the case.
The voltage surge will damage that rectifiers and charge resistor and potentially the output stage as well, but generally it would be limited to the input stages.

The best level of protection, is to disconnect the drive or starter from the supply when it is not running. This can be achieved by the use of a line contactor. While this is relatively commonly done with soft starters, it is not common with drives. In some cases, switching the input On and Off will weaken the drive input stages.

Voltage surge protection can be built into the input stage of the drive, but this can cause major problems if the fault capacity of the surge is very high. The fault capacity can be reduced by the addition of line reactors upstream of the surge protection.

I would suggest that you talk to your supplier and get their recommendation for their equipment.

Best regards,

[subhash]

Thanks Marke
realy it is better to of our equipment when not in use but for stand by system it is our limitation to make power off of this system due to some other interface with our m/c ,
please suggest yuor view on if we monitor continiously input voltage level and in case of power dip or surge
is there we will trip input supply Circuit breaker of the system ,
and now question is that which sensing relay will sense this surge effectively and how reliable this protection is , please suggest your views on this

Regards
Subhash.

[marke]

Hello subhash

No, I would not consider sensing a surge and opening the breaker, by the time this happens, the damage is already done and the breaker would probably have opened under fault conditions.
Surge protection is usually achieved by a device that breaks down under voltage before the protected equipment breaks down. When the protection device breaks down, it diverts the fault energy through itself and usually causes fuses to fail, or breakers to open. The protection device should be designed to withstand the maximum fault energy that is likely to occur until the fuse fails.
The line reactor will limit the peak energy flow.

Best regards,

[subhash]

Marke
Thanks for suggestion ACS600 type of ABB Having inbuilt line reactors for fault protection
But we think it is better if we go for surge supressor in power circuit. It will avoide further damages in future and will protect drive better.I would like to know where i should put these Surge supressor as Our present set up is ACB + Semiconductor Fuse +Drive My plan is to put surge supressor in between ACB and Fuse is it correct or it should after fuse and before drive.
or will you suggest any better protection Scheme . In Our present Circuit for 325 Kw motor drive we are using 700A is it correct.
Please reply
Regards
Subhash

[mariomaggi]

Subhash,

But we think it is better if we go for surge supressor in power circuit.

considering the failures happened, I would recommend to add a line reactor.
Semiconductor-type fuses are not so necessary, usually. Fast fuses are enough fast, but please follow indications on the ABB user guide.
Regards
Mario

[marke]

Hello subhash

The surge suppressor device will attempt to short out the surge and it therefore has to dissipate/absorb a large amount of energy. If the surge is to high, the surge protector will explode unless it is properly fused.
If the surge protector is fused on it's own, then its protection fuses will open and let the surge through to the device that you are trying to protect.

It is best that the surge protector is used to blow the fuses in the main supply, therefore you need to install it down stream of supply fuses. Line reactors will also limit the magnitude of the surge energy making it easier for the surge protectors to limit the surge without being damaged.

Upstream fuses and line reactors can be used to limit the fault current at the drive input. The surge protectors should be connected after these devices and sized such that they are able to withstand the fault current determined by the fuses and line reactors.

If the fault current is relatively low, you do not need the line reactors.

Best regards,

[subhash]

Hello subhash

The surge suppressor device will attempt to short out the surge and it therefore has to dissipate/absorb a large amount of energy. If the surge is to high, the surge protector will explode unless it is properly fused.
If the surge protector is fused on it's own, then its protection fuses will open and let the surge through to the device that you are trying to protect.

It is best that the surge protector is used to blow the fuses in the main supply, therefore you need to install it down stream of supply fuses. Line reactors will also limit the magnitude of the surge energy making it easier for the surge protectors to limit the surge without being damaged.

Upstream fuses and line reactors can be used to limit the fault current at the drive input. The surge protectors should be connected after these devices and sized such that they are able to withstand the fault current determined by the fuses and line reactors.

If the fault current is relatively low, you do not need the line reactors.

Best regards,

Hi Marke & Maniomaggi
Thanks for suggestion is there any better protection scheme for Drive & Softstarters That we will kill this type of voltage surge problem please suggest .
Regards
Subhash.