Am currently studying 2391 and wonder if someone could advise me on some things that are confusing me.
1) In Hinsleys book, Testing Electrical Installations, he quotes some examples of PSCC he talks of measurement or calculation. I quote ' Assume you have a reading of 0.10 ohms, you need to divide the voltage at this point by the resistance, e.g. 230v/0.01 ohms = 23kA'. My question Is he correct to use Uo 230 rather than Uoc the transformer voltage which could be 240 or more at time of measurement?
2) When measuring PSCC are the only relevant points to be measured at the origin of supply and origin of a circuit(at the breaker)?
3) When testing Zs on 3 phase motors Hinsley says that MEB should be disconnected......surely that can't be right?
4) Also when doing Zs on a small induction motor Hinsley says remove the star/delta links and test at the motor. We are being taught that the circuit should be broken down into sections and measured and then a calculation made . How would you personally measure Zs on a motor?
1) In Hinsleys book, Testing Electrical Installations, he quotes some examples of PSCC he talks of measurement or calculation. I quote ' Assume you have a reading of 0.10 ohms, you need to divide the voltage at this point by the resistance, e.g. 230v/0.01 ohms = 23kA'. My question Is he correct to use Uo 230 rather than Uoc the transformer voltage which could be 240 or more at time of measurement?
2) When measuring PSCC are the only relevant points to be measured at the origin of supply and origin of a circuit(at the breaker)?
3) When testing Zs on 3 phase motors Hinsley says that MEB should be disconnected......surely that can't be right?
4) Also when doing Zs on a small induction motor Hinsley says remove the star/delta links and test at the motor. We are being taught that the circuit should be broken down into sections and measured and then a calculation made . How would you personally measure Zs on a motor?