Quick Answer: What Is IR Setting In Mccb?

What is IM setting in Mccb?

(C) Short Time pickup Current Setting (Im): The short-time pickup (Isd) sets current level (below instantaneous trip level) at which circuit breaker will trip after the preset time delay..

What is IO IR ISD?

‘Io’ is the course setting for the ‘long time’ protection threshold. ‘Ir’ is the fine setting for the long time protecton. You work out you overload protection using In x Io x Ir. Isd is the threshold of the short time pickup.

What is LSI breaker?

LSI — A combination of adjustable trip functions including long-time ampere rating, long-time delay, short-time pickup, short-time delay and defeatable instantaneous pickup.

What is UE voltage?

Ue = 110 VAC … is the voltage measured across the load of a closed (conducting) sensor at load current Ie. … of the power supply for AC devices is 50 to 60 Hz.

How do you read circuit breaker times current curves?

To determine how long a breaker will take to trip at a given current, find the level of current on the bottom of the graph. Draw a vertical line to the point where it intersects the curve. Then draw a horizontal line to the left side of the graph and find the time to trip.

How do you calculate the breaker setting on a circuit breaker?

How to Calculate Circuit Breaker Trip SettingsLook for the amperage notation on the breaker switch. This will generally be 15 or 20. … Multiply the amps by the volts. In most circuits, this will be 20 x 120 = 2400 or 15 x 120 = 1800. … Apply the same calculation to 240-volt circuits. … Check the wattage for all electrical fixtures and appliances on the circuit.

What is IR and IM in Mccb?

Ir: Overload (thermal or long-delay) relay trip-current setting. Im: Short-circuit (magnetic or short-delay) relay trip-current setting. Ii: Short-circuit instantaneous relay trip-current setting.

How do you set an instantaneous trip setting?

The instantaneous trip setting for larger molded case and power breakers can usually be adjusted by an external dial. Two instantaneous trip settings for a 400A breaker are shown. The instantaneous trip region, drawn with the solid line, represents an I.T. = 5x, or five times 400A = 2000A.

Does Mccb trip on earth fault?

Usually, arcing ground-fault currents are not large enough to be detected by the standard MCCB protective device. But, if left undetected, they can increase sufficiently to trip the standard protective device.

How do I set up Mccb?

Long Pickup (Ir) value (multiplied by the ampere rating (In) of MCCB) sets the maximum current level which the circuit breaker will carry continuously. If MCB is 1000A Rating but Full Load current is 800A than MCCB Rating can be changed from 1000A to 800A by setting it 0.8, Now Ir=0.8XIn =0.8×1000=800Amp.

How do I read Mccb nameplate?

How to Read MCB Nameplate Data Rating Printed on it?Model Number.: All reputed manufacturer has a particular code of each device type. … MCB Current and Curve Rating: As shown in example, it is mentioned C20 (and in the below image, it is B25). … Operating Voltage: It is in Volts and is the operational voltage for which current rating is said.More items…

What is ISD electrical?

Isd: short time (“magnetic” or “Im”). This is a multiplier of the Ir setting, often 1.5 to 10 times the Ir current. Role: protection against short circuits. … Role: protecting the installation against strong short circuits (dead short circuits) by instantaneous tripping and self-protection of the circuit breaker.