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Cable short circuit dynamic I peak value has been requested by switchboard supplier. This cable is used to connect between two DC switchboards(VFD) to drive VFD motors. It seems that this is not thermal data. Can it be informed by cable manufacturer ? Can anybody explain what it is and what it...

The Ex-cable glands is provided with armor earth on the cable gland but I'd like to find cable brand or type of non-ex cable gland with armor earth provision. This is intended for avoiding seperate armor earthing.

I was reported that the sodium flood light went off when large motor was starting. sodium flood light(220V) is fed from emergency lighting switchboard while large motor(6.6kV) is fed from main switchboard. 2 minutes later flood light is back on. What are all possible reasons we consider and what...

The test panel is used for driving various motor after repair. It is able to drive motor up to 120kW, 460V 3phase. In order to hook up motors to test panel, test panel needs power lead outlet(i.e power socket/plug). Now I am finding provisions manufacturers supplying outlet or any other means.

I am not familiar with generator. I have seen fixed droop and compensated droop on certain document. What are those different from each other ? What are impact on speed control ?

The explosion proof equipment is normally designated as protection type such as EXe Exd or so on. How do I know protection type from designation from US vendor. The only thing I obtain from vendor site is to give the kind of Class and Div. The designation does not identify protection type in US...

I'd like to check braking resistor sizing of VFD. What philosophy is used in sizing braking resistor, i.e. how to size braking resistor.

I placed the order of cable with cable tech spec; "control multicore cable with armor and common shield" However, potential supplier proposes that shiled be deleted from cable construction because armor can function for shielding. It is understood that armor works as shielding but I'm not sure...

Normally, the shield of instrument cable is locally earthed at local cabinet. However, some customer requires that all I.E cables for each earth bar of local cabinet be rought to dedicated/isolated earth bar from I.E bar of each local cabinet. The dedicated earh bar is insulated and dedicated...

The air cooled braking resistor for VFD is built in U.S and its ingress protection is 3R as per NEMS standard but sepcification requires IP56 for outdoor installation. 3R is equivalent to IP14 which is not suitable for outdoor installation. However, 3R is also for outdoor installation. I believe...

There are earthing transformer directly connected from 11kV switchboard and earthing transformer is of Wye(neutral grounded)-Delta(broken delta with resistor). However, I did not find connection from neutral point of generator. This is first experience to me. First, I am not sure if earthing...

It is found that circuit breaker shall satisfy that the r.m.s symetrical breaking current for which the device is rated is to be not less than the r.m.s value of the a.c component of the prospective fault current, at the first half cycle.(previously at the instant of contact separation)...

I have experiened Droop mode in general, but didn't ISO mode. Why is ISO mode adopted ? Anybody explain two different modes, application, and effect on governor. welcome to tell me website.

Would you please summarize differences between starter based on IEC and starter based on NEMA ? or please let me know helpful site.

Six step-down transformers(6.6kV/440V) are used for refregerator containers. These are fed from local power socket box via local power distiribution board. There is MCCB in the the local socket. This MCCB does not withstand estimated fault current. As a measure, I am considering significant...

The relay is not of solid state relay. If relay is changed to DC relay then I also should be careful of voltage drop over the long cable. That's why I prefer to AC circuit.

The normal closed contact(low level) of float switch is connected to relay in the starter but relay does still energized when level reaches low. The relay is driven by AC220V. I swapped relay and circuit with DC24V instead of AC220V, then the realy is working(drops). The contact is laid with...

Here is attached one line diagram.http://files.engineering.com/getfile.aspx?folder=e36cd2ab-bdb2-4f58-b03d-5b1b8c25ea8e&file=one_line.pdf

The 6.6kV switchboard consists of 20 cubicles having earth bar and each earth bar is connected with each other, i.e same potentail is kept between each cubicle. In order to earth to ground, dedicated cable to connected to ground from earth bar at each cubicle, 20 earth cable. But, I think 20...

I am sorry that my explanation is very poor. I enclose power distiribution one line diagram. The voltage drops at motor starting and voltage is stablised when motor reaches rated speed. If another motor is started, voltage drops lesss because the first motor is in operation. This means that...