Possible to detect a motor is connected to an inverter?

[Bobobodopalus]

Hi all,
I am trying to find a way of detecting a motor is not isolated before attempting to run an inverter.
We would normally use a 4 pole isolator and use 1 pole as a monitor but in this case it has to be a class 1 division 2 isolator and i cannot find anything which is 4 poles and 30A/10HP rated.
This is made a bit harder by the fact we are a company in the UK trying to source american items.
any suggestions of a way of doing this would be welcome, the inverter is a PF525 400V 7.5kw

 

[chud]

Most Isolator manufactures will have a add-on auxiliary contact for open or closed indication

 

[Bobobodopalus]

I have not been able to find one, we have a 3P isolate here its a square D 2510 KR2H i have not seen any additional contacts listed anywhere

 

[Puddle]

You may have more luck finding something with the equivalent ATEX rating. If you can get it signed off that is.

 

[Bobobodopalus]

While easier, its a no go, has to be C1 D2

 

[parky]

perhaps contact Stahl seem to remember these being used in an class 1 explosive area.

 

[5618]

The Square D you listed is a manual starter. Look at Eaton / Crouse-Hinds EBM and Hubbel / Killark B7NFD. Add the word ‘disconnect’ to your Eaton search or you get Extended Battery Module.

 

[Bit_Bucket_07]

The Square D you listed is a manual starter. Look at Eaton / Crouse-Hinds EBM and Hubbel / Killark B7NFD. Add the word ‘disconnect’ to your Eaton search or you get Extended Battery Module.

Square D IEC manual starters do support auxilliary contacts. I recently ordered and installed some, and although I couldn't find the aux contacts in the starter documentation, my local distributor knew how to order them.

 

[L D[AR2P#0.0]]

Why not run the inverter, I would expect a fault code to come up indicating there is no motor connected.

 

[Bobobodopalus]

Will have a closer look at square D..
the inverter would go into a fault condition and need to be reset, but ive always been warned against attemping to run larger inverters without a load so it would be better to just prevent the run

 

[jraef]

Cl. 1 Div. 2 is the real challenge. Search for “NEMA 7 non-fused disconnect”. That’s how they are marketed here.

This is an example. Inside of the NEMA 7 box is a standard ABB rotary disconnect that you can buy an auxiliary contact for.

 

[jdbrandt]

Hi all,
I am trying to find a way of detecting a motor is not isolated before attempting to run an inverter.
We would normally use a 4 pole isolator and use 1 pole as a monitor but in this case it has to be a class 1 division 2 isolator and i cannot find anything which is 4 poles and 30A/10HP rated.
This is made a bit harder by the fact we are a company in the UK trying to source american items.
any suggestions of a way of doing this would be welcome, the inverter is a PF525 400V 7.5kw

525s have an alarm when the motor wiring is not complete. It is disabled, by default.

 

[jridge]

525s have an alarm when the motor wiring is not complete. It is disabled, by default.

Good idea, I had to look it up since I haven't heard of it before. It is parameter A557. "Out Phas Loss En"

 

[GaryS]

I would be very careful here
Opening or closing a motor load on a VFD could destroy the VFD I have seen this many times itÂ’s even worse on the larger motor
The larger VFD use high current SCRÂ’S to supply the current to them motor
But for an scr to turn off they relay on the ac cycle passing through 0 or to more prepensely when the voltage start to go negative . if you open the circuit before the that happens the gate on the scr keeps it open and when the other leg turn on the current flow will destroy the drive.
The same thing happens if you switch in a load on running vfd the sudden current inrush can destroy the vfd
Even o the smaller vfdÂ’s the newer ones use IGBTÂ’s bt their again they are never fully ON or OFF they just go from very high resistance to very low resistance very quickly so they can tolerate thing better
You should only switch the output of a vfd when the vfd is fully off
And always remember even a vfd thatÂ’s off still has enough on the output to give you good shock or even kill you
Mode vfdÂ’s today have output and input phase loss protection that will shut the drive off if there is a problem
Remember Lock Out, Tag Out and verify everything

 

[parky]

Most VFD's these days do not suffer with that problem, it used to be the case, we had over a dozen machines where two motors driving screws were connected to one VFD & the output of the VFD had an arrangement of 3 or 4 (cannot remember now) contactors, so it could change the direction i.e. both going FWD, both going Backward or both going in opposite directions & these could be reversed. this happened about every 30 seconds the idea was to mix product in a specific way & discharge at one end, considering these machines ran at least 16 hours a day 7 days a week & were installed in 1996 & still going in 2019 during my time we never last a VFD due to a fault, only had one & that was when an operator filled it with water while deep cleaning the plant.