circuit breakertransformer
I have two Miniature Circuit Breaker, so one is ordinary main Miniature Circuit Breaker(house main MCB) in range of 25A and the other is my device (Auto-Transformer) in range of 16A, So when i run the Device some times first Miniature Circuit Breaker(25A) work and cut the power line, So my question is why not the second Miniature Circuit Breaker working first, dose it's come back to that quality or any other setting like it's Trip characteristics?
The MCB 25 A:
The MCB's 16A:
Thanks a Lot.
It is unlikely that the red wires actually have no continuity if they are really the primary winding. If that was the case, the transformer would do nothing when connected to the mains circuit. If you are using a multimeter to check for continuity, it is trying to measure impedance and give you a value in ohms. I have found that cheaper multimeters seem to get confused by the high inductance of the primary circuit of small transformers. I have known-good transformers that read no continuity with my cheaper multimeters.
An alternate test for checking continuity is to wire the primary in series with a circuit that has a DC current. For example, a 5 VDC power supply, a 100 ohm resistor, and a cheap LED. If the LED lights, the circuit has continuity. The LED must connected in the correct direction to be forward biased. This is a cheap, effective circuit for checking DC continuity. The peak current is only 50 milliamperes, so it is unlikely to cause damage to the transformers winding. The LED will be a bit unhappy at this current level but will not die instantly.
If you have a transformer that is tripping an RCD (also called as a GFCI), there are a few possibilities
You have connected it wrong. The circuit theoretically can work using the line and ground wires. This is unsafe however, this trips the RCD. It's also worth mentioning the outlet could be wired wrong. However, in that case anything plugged into that outlet should trip it.
The transformer is shorted to its metal case. If the transformer has its 220 volt primary shorted to its metal case (even with a very high impedance) it is allowing current to flow from the line to the ground. This trips the RCD. This is very dangerous if it is true. You can test for this by placing the transformer on a very good insulator, like a sheet of plastic. If you have a kitchen cutting board that is plastic and white in color, that could be used. If it does not trip the RCD when placed on an insulator, it is likely that it is shorted in someway. Do not touch the transformer whatsoever while performing this test.
You have an RCD that is also an arc fault detector. Some RCD breakers have a circuit to detect the energy from an electrical arc and trip. It is possible that due to poor manufacture or lightning damage, there is a tiny arc in the primary of the transformer. This is usually the result of several turns being shorted together by a carbon track from a lightning strike.
It is difficult to know what you think your circuit will do and your explanation is very poor. However some misunderstandings need to be corrected:
If you insist on working on live equipment then you should use an isolating transformer.
simulate this circuit – Schematic created using CircuitLab
Figure 1. Bench test mains power supply.
How it works
That should help you sort out most problems on the bench.
Forget your virtual earth circuit. It is not safe.
Best Answer
Looks to me like both of those are 16A actually, but one is a B curve and one is a C curve, the C curve breaker is normally used for motor and transformer loads precisely because it has a curve that suits these loads.
A type B will usually trip before a type C on a startup surge.
Type B is normally seen in domestic applications where very large inrush is less of a problem.