Can someone give me some insight into what would happen at the motor terminals and on the line if 2K2 (run Contactor) and 2K3 (auto xfmr wye contactor) were to close simultaneously. There are interlocks to prevent this, but I would like to know out of curiosity. My theory is that you would have...
Baluncore — never looked at it that way. That correction will help.
The difference in a power transformer and a current transformer being the voltage on the primary, there is no transformed voltage in a ct. But a voltage must still be present across the secondary for a current to flow.There is...
Zoki - The only problem is that there are holes in my understanding. The question was more about helping me learn the relationship between E and I in a CT. The coworker and job really isn’t relevant. The GF system is malfunctioning, he checked the CT voltage to verify the condition of the CT...
Since there appears to be no burden resistor internally, and a digital voltmeter will have a very high input impeadance , I would say there is no way to get an accurate measurement of the CT output by measuring voltage on the secondary only. Current and voltage may not be proptional. It will...
Yes. The manufacturer literature says to short “c” and “m” to prevent shock. It’s a 3 wire zero sequence CT for ground fault protection. The current from the CT energizes the trip coil. I’m just having a hard time reporting his 130v @ 400a to the customer because it seems wrong. The CT is a GE...
Zoki the steady state capacitive current in AC is small and inherent in the circuit, but the displacement current through a capacitor equals the conduction current at the capacitor, correct?
I don’t know the ratio of the CT. I’m just looking for an explanation on this. I thought in order to measure output voltage you need to pass the current through a resistor and read the voltage drop.
A co worker put 400a through the CT and measured 130v. Something just seems off to me. Can you...
And the same applies to both ac and dc correct? A charging or discharging dc capacitor will have a changing electric field which would cause the displacement? I’m an electrician, no one explains capacitors in this way. “A charge on one terminal pulls a charge from the other side” etc. (I’m...
What allows it to pass through a capacitor dielectric at that frequency? The voltage at the capacitor plates would have the same frequency as an interrupter contact, right? Just curious. Thanks for the quick reply.
I’m self taught so I have a lot of holes in my understanding. I also have little to no mathematical understanding. Even though ironically, I tend to prefer to picture electricity as numbers rather than “water” in a pipe, etc.
I’ve been studying displacement current recently and have a question...
To answer the questions top to bottom, it is not an earthed neutal. It is on an equipment ground. the current is constant during operation. The ground is terminated in the peckerhead and does not enter the motor.
If the grounds were open between the motor starter and switchgear I would expect...
In the attached picture, I’ve drawn a crude schematic of the motor circuit. It is fed from a switchgear feeding 3 total motors.
The feed contains 2 parallel conductors on each phase and ground. The equipment ground reads 12a going back to the switchgear, 6a per conductor. From the starter to...