This may sound a little stupid but I was just wondering if the kW losses (due to I^R) is also metered by the kWHour meter. I believe that the kWHour meter can see this but unfortunately it cannot distinguish between losses and useful power.
Hi all,
I am aware that NEC requires 125% over-rating factor maintained on top of cable deration. I have a transformer with a secondary full load current. I'm sizing it to be equal to 125%FLA/de-rating factors...then select the cable size.
However, if these cables are connected to a...
I would like to inquire as to what X/R ratio medium voltage circuit breakers are generally tested to sustain their S.C. ratings.
Appreciate any help. Thank you.
I have a 75HP motor with power factor 0.85,efficiency of 0.95 and load factor of 0.98. The nominal voltage is 600V and the motor utilization voltage is 575V
I have a spread sheet showing a FLA calculation using the motor utilization voltage which would end up to be 69.57A.
Using nominal...
I have received a Utility Data for me to model the Utility in the SKM program.
The Data gave me the LLL, LL and LG maximum utility fault contribution. It also specified the "Thevenin Impedance" in X1, R1 and Xo, Ro at 100MVA utility Base. I assume that these impedances are in P.U.
However...
We have a 13.8kV solidly grounded system where the short circuit is relatively high.
One of my colleagues are specifying a NEMA E2 class starter to feed a padmounted distribution transformer. The 51G at the secondary is proposed to be wired to to trip the upstream contactor.
My concern is that...
In an ungrounded system, it is proposed to provide a Wye(neutral grounded)primary-Broken Delta Secondary with a 59G relay connected and a 67N. The 59G will supervise the 67N which in turn will trip the incomer circuit breaker.
I read some articles on this but I would like to request guidance on...
I have a heat trace controller used for heating insulated busbars for an overhead crane installed outdoors.
The minimum ambient temperature during winter time here is -40 Deg C.
The controller box has a Thermostat controller rated for
-34 to +66 Deg. C (Operating)
-40 to 85 Deg C (Shipping)...
Hi all. We have an HVAC MCC supplied by one of our vendors. In their systems, they have provided Device Net Devices for communication and provided 24Vdc power supplies within the 600V MCCs. The power supply is supplied by a 600V-120V step down transformer feeding two units of 120VAC-24Vdc power...
I have a little circuit which do some VFD pre-charging. The coils are operated at 120VAC and one of the out contacts is used to close a circuit breaker rated for 125Vdc (Potter Brumfield KUEP-3A15-120).
Due to limited space for putting a separate wireway, the wires are inevitably installed in...
I would like to have an idea on what is the purpose of surge protection on industrial type relays.
I am using an industrial type relay as an interposing relay for closing a circuit breaker. The contacts on this relay are well rated for the breaker closing coil duty at 125Vdc.
The coil is...
We have 7.2kV, 1200A, ABB Advac Circuit Breaker feeders. In the associated breaker internal wiring diagram, we observed that there is a "close blocking switch" in series to the closing coil/anti-pump device.
I would appreciate if anyone who had experience on these breakers share their knowledge...
I have a TEFC motor which is rated as "Bi-Directional"
If we decide to change the motor rotation direction by swapping A and C leads, do we need to mechanically change the cooling fan impeller to match the new direction?
Regards...
Underpower protection element is available on most multi-function motor relays. This is used to protect the pump against cavitation due to underloading or in the case of dry running.
My question: Is there any guidelines on which kind of pump this is used. It is ideal for submersible pumps but...
We have submersible pumps with 28" lead wires. The problem is that we do not have drop cables for them.
I would like to know what type of cable would be suitable for submersible applications? Can I use a TECK cable?
Are there splice kits for a 3 core cable to 3 x 1C wires?
I have required digital input wiring from a switchgear to a VFD terminal strip rated probably <24Vdc. At the same time, I have digital outputs (dry contacts) coming from the same VFD terminal strip to the switchgear and these contacts will operate on 125Vdc powered from tge switchgear.
My...
I am looking for an industrial type relay, form c, 11 pin, 10A.
I checked potter brumfield but their relays are all rated 110Vdc max.
can anyone provide other brands? I am based in Alberta Canada
I'm in the CSA world for lightning protection.
We have a project which involves a structure of >25 meters. The building is structurally interconnected with steel walls and roofing. There are HVAC, air vents, steel platforms, stanchion mounted lighting and water steel piping. I considered the...
We have short transmission lines fed from an upstream power transformer with a 200A NGR secondary system.
The consultant has provided Ground Impedance settings for the distance relays on the load end substation. Is the ground impedance settings on the distance relays going to work or is...
Does anyone had experience in setting Siemens Robicon Perfect Harmony WCIII? We applied this VFD for a 7500HP motor with input voltage of 7.2kV and an output voltage of 0-7.2kV
I received a worksheet from the vendor requesting for VFD settings with descriptions that I am not familar with like...
