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dear sir 2.6MW 6.6KV induction motor ,gives low resistance with 4Mohm and was tripping with earth fault current (with fault current=42Amp),the network neutral connected to ground through 150 ohm resistor. and because no signs of any winding damage ,we decide to condensate the winding to remove...

dear all The mentioned motor 2600kw 6.6kv was tripped by earth fault (50N/51N),after disassembling the motor found the insulation resistance 4MΩ ,no sign of burn or moisture inside winding ,all winding all the physically checks shows no sign of damage .we tried to clean winding by air but we...

dear sir we are going to establish new job plan for testing multifunction protection relay (sepam for schnieder), i need forms for testing each protection units,,,,

dear sir is there any effects of applying insulation resistance test many times for windings?

dear sir we need to plan new preventive maintenance for our electrical equipment in our plant what is the frequency of doing this maintenance(1M,6M,or12M)? i need to modify our job plan so it there any recommendation of PM job plans?

dear all we aimed to issue a new data base for electrical site equipments ,so we can monitor the curve of insulation resistance during time pass,create a history of replaced spare parts of the equipment,using excel sheets or other prog-,i need some more ideas or forms for how to create such...

dear all we have got a sepam 1000+ M21 where most of sepam goes to failure mode (code 1)(maijer fault),in case of i switch the sepam power supply ,where i must replace it with new sepam if i switch it off???

Dear electrical experts.. i need ur help for how to functional test ABB motor overload single phase current generator.is it correct to loop the singlephase over the three overload poles but the results i got is with larg diffrent with the over load cure.plz help

hi electrical experts we are tending to preform protection functional test for our feeders in power center plz help in the following questions: 1) what is the stander for frequency of applying protection (each 1y,2y or 3y)? 2) what is the minimum difference of overload unit trip time between...

dear electrical experts the generator type RS14 14KVA shutdown directry when battery are disconnected . note the generator has no separte altenator for battery charging and the main output power is O.K ?? The second question ,our tow new generators have dameged diode(this diode connected...

a power generator has the following nameplate data (13.6KVA ,400V 19.3A & pf0.8) at the begining when i calculted the current s=IV so i=34A but the nameplate current was 19.3A whish is = (34/1.73 ) why it was calculated with that way.

dear all what would be the function of the parallel capacitor use with flood lighting . and what the causes that damage it? thank you?

hi If i knew the current flows in each phase,could i calculate the leakage currents(F64 anci).or even the neutral current

hi all How much important tacking in considration triplen current How could i calculate triplen current flows in neutral,to chose the neutral cable size? What kind of loads create it ? Is the electronic ballast of lighting creates triplen ?? Thank you.

sepam 1000+ M20 After restating the sepam(power off & on),sepam goes to (failure safe mode) showing failure code 1(Majer fault) and wouldn't comes back any more. This problme happend with many of our sepams in site. Could we restore it back? And what is each failure code mean? Plz help!?

hi all could the core blance CT (eart foult protection ) detect the unblance in phases current or it's detect the leackage only? what is the reasonse of staturation of core balnce ct?and is it useful to shot CT pole to dischare the saturation?

dear elecrical experts; -in all of 4 cores cables the neutral is less by 50% of each phase core,whay is 50%? - for (3ph-N) power supply feeds single phase loads so the neutral should have the sum of currents of the 3 phases,whay that isn't true. plz help.

dear electrical experts, what's the effects that could appeare in case of eath foult current flows through the ground network coused by deffected motor (the system has no eath foult protection for tripping)?and how could that afect to the power generator?

hi all, i have face this protection units (zero ,postive ,negative sequence )in protection relay (IMM9000 from CEE).so i didn't get the diffrent btewwen zero squeance and earth foult,positve squ- and short and negative squ- and unbalance ?and if thay are the same why thay call it by...

hi all can iuse ground point to get 230v from 3ph 380v perkins 800kva .to get 40A for using in lights and scokts.