We have two 30kw motors connected in parallel to a 75kw vfd. The motors are mechanically coipled to the load. In these cases, my knowledge says that the VFD can only work in V/F mode and vector control should not be used. But surprisingly, The VFD has only a vector mode and is set on Closed...
Hi we have a 20 tonnes crane run by a 60kw electric motor and its VFD. The dynamic braking resistor connected is 3.5ohm but we need to know the wattage of it and its model qnd brand is not clear.
Is there a way to measure or calculate the wattage of the braking resistor?
Hi all. We have bought an AuCom MV softstarter panel and are arranging the delivery. We are already late in our project and need to do it by air, which needs the panel to be placed on its side horizentally. Some speciallists believe that doing so would damage the softstarter capacitors or other...
I was choosing contactors for DOL starting a 690v motor. I was reviewing the specs of Schneider LC1F400M7. It is written:
200kW on 400vAC. This means the rated current is about 400Amps on 400vAC.
280kW on 690vAC. This means the rated current is about 280Amps on 690vAC.
Why the contactors is not...
I know ANSI46 can detect unbalance conditions very well but I am trying to understand the unbalance protections for a distribution transformer via 50N, 50G and 50GS.
Our network uses delta/grounded wye transformers, so the protection scheme would be as below based on IEEE 242 book ...
I have just heard of a brand for protection relays and comms solutions with name ZIV. I have not yet worked with their devices and don't know how is their quality. Is anybody familiar with them? How is their quality and level?
Hello all.
I have some issues with PT wirings. your help is appreciated in advance.
1- can Wye PT wiring (3 PTs) provide phase angle measurements?
2- the figure below shows the connection of a single PT to Schneider Vamp40 feeder protection relay. the manual says that with this configuration...
We have a single phase motor. we also have a vfd which supports PSC( permanent splitted capacitor) and single phase Shaded pole motors. The pictures of the motor plate and the capacitor on it are attached.
Is this motor categorized in any of the supported types, i.e. PSC or shaded pole? How can...
Hello
I am struggling in finding the proper contactor for my requirement. I have an application which needs a contactor that satisfies the below characteristics:
690 Volt
1200 kW
1200 Amp
please refer me to brands and models available in this range. please provide the exact model as I searched a...
I have recently studied core balance CTs and the only criteria provided for selection was the diameter. How should I choose the proper core balance for my application? For example consider having a 3*70mm2 three phase cables. what is the proper core balance diameter for this application? I have...
Hi everyone,
I'm working as the technical director in a power equipment-supplying company. We work with different distribution protection relays. Some of these relays are FANOX relays which provide 50:instantaneous over-current function. The minimum operating time of 50p function in these...
