I have Siemens make 150hp (164FLA), 460V motor (IEEE-841, premium efficiency) is causing main HMCP to trip on start-up. PdMA results shows all OK (PI-10; DDA-1.9; Average Phase resistance & inductance 0.0635ohm, 2.008mH)
Inst. Breaker set at 13*FLA. No problem with cable or starter.
Is motor...
I have two identical 4000hp Synchronous Motors operating reciprocating compressors. The ‘–ve’ terminal brushes on one machine tend to develop spark. The excitation control system (GE-Stat-x-ator) has almost the same volts/amps/pf for each machine, as the loading is identical. Need help to find...
I need help to solve a puzzle where some of the feeder breakers for healthy circuit were tripped cause of fault in one feeder, connected to same bus.
Problem started with failing of few capacitors of capacitor bank and caused the tripping of capacitor bank feeder breaker on 3-phase instantaneous...
Hi Every body
I am looking for Three (3) copper conductor, 350 MCM, 15 kV, 133% insulation level with semi-conducting thermosetting layer as well as metallic tape, cable with EPR (Ethylene Propylene Rubber) insulation, shielded and PVC jacketed, HL rating & flame test-rating FT-4, CSA approved...
Hi Every-body,
The API 541 deals with motors above 250hp in Petroleum & chemical industries. The question I have is which API or any other standard deals with motors below 250 hp in Petroleum & chemical industries.
HI,
For single-phase system (Phase & neutral), the load is at ‘X’ distance form the source and to calculate the voltage drop in the cable, shall I use 2X distance (X-for phase wire + X-for neutral wire) or just X-distance?
Hello,
I had two questions
1) Why utilities are using Y-Y connected transformer for power distribution? The only advantage I see is the cost (less insulation). Are there any other advantage/ disadvantage of using this type of transformer?
2) What are the disadvantages if both the star points...
Hi,
Normally at each plant we had both medium voltage & low voltage motors. The low voltage or medium voltage distinction is based upon kW rating of motors. I am interested to know the factors which identifies the maximum size of motor (kW) is suitable for a particular system voltage.
Thanks in...
I am planning a system which will have redundent motors(Stand-by or spare for running motor). My question is how to calculate future demand shall be from this load. Shall I consider the future demand shall be only from running motors or shall consider the future demand shall be 80% of total...
Hi Every body
I Had a circuit where three components, connected in series (2000-ohm resistor then Indication lamp & then relay coil) across the 125V DC source. These components are rated for 120 V DC. Under this situation the relay coil didn’t get energized because of not sufficient voltage to...
Hi Everybody,
I had situation, the out-door type transformer (ONAN)transformer to be installed nearby (2ft horizontal) to natural gas line (Burried 3ft U/G). Is it acceptable or any Hazar or other complication involved in it? The feed to transformer is 4160V via teck-90 cable & FT-4 rated...
Dear Members,
I had confusion regarding converting impedance in PU system. A 3-phase transfomer(5MVA, 13.8/4.16kV & 7% impedance) connected to source (Fault level 255MVA). The load connected on 4.16kV is 2000hp (suppose impdance-Xpu). The base MVA-100 & base kV-13.8. For calculating the PU...
Dear Members,
For a project I am using 22AWG solid tinned copper, 100-pairs twisted cable for telephone distribution system in a Hazardous plant enviorment using cable trays. What other electrical charactristiccs need to be specified in order write down the specifications of this cable.
For 3-wire RTD (has Hot, Return & Compensation) is their any max. length of RTD cable can be used. As my under standing is using compeensation max. length should not be limitation.
