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How overload relay works?
An overload relay is fundamentally a board that protects the relay from overloads. It works on the science of being an AC inductor..
What is the function of an LBB relay?
A local breaker backup relay is used to check the operation of distribution circuit breakers and to trip the feeder circuit breaker if the distribution circuit breaker fails to trip on an overload.
What is the cause of the compressor if not trip to its overload?
What is the cause of a compressor if not trip to its overload
Overload Trip Class - What does it really mean?
Quite often we here of applications in which the motor protection/overload relay 'trips' during motor starting. The remedial action taken by many when faced with this problem is to select and install a replacement overload relay, generally one that provides a higher 'Trip Class' setting, for example, Trip Class 20 in lieu of the standard Trip Class 10.Note: The appears to be a general misconception in industry that Overload Trip Class relates directly to the starting time of a machine. This is not the case.All due care must be taken when selecting a protection relay offering higher Trip Class, as this can result in under protection and subsequent failure of the motor.To select an overload relay with a more suitable trip class, you must in the first instance obtain data relating to the motor's thermal withstand capabilities. That is, you need to know how many seconds (from cold condition) the motor can the sustain Locked Rotor Current before it is compromised.This information is readily available from most leading manufacturers of motors and is generally provided in one of two formats.a) Specific values for Locked Rotor Current and maximum Locked Rotor Time (from 'cold condition' ) are given.b) A Motor Thermal Withstand Curve is provided.With this information available to you, you can refer to the tables given in IEC 60947 to identify the most appropriate Overload Trip Class. This is defined as the one that provides a trip curve as close as possible to but below the overload curve of the motor. Adopting this process will ensure nuisance tripping is minimised and that the motor is adequately protected at all times.Note: If the above processes are adopted but the trip conditions continue, there are 4 possible causes.1. The motor (and overload relay) are not given sufficient time to cool between starts.2. Assuming reduced voltage start (star/delta, auto-transformer, primary resistance, soft start etc., the motor is not delivering torque sufficient to accelerate the connected load to speed. That is the starting current and starting time under RVS conditions exceeds that permissible by the overload curve.3. A more advanced protection strategy such as motor thermal modelling may be required. Motor thermal modelling allows the user to 'match' the curves of the protection device to the connected motor. This is of particular advantage when the motors thermal withstand capabilities and the start condition (starting current and starting time) fall between two curves defined by standard overload trip classes.4. The motor is simply too small for the application.Put simply, the most appropriate protection strategy is the one that allows the motor to be fully utilised without nuisance tripping or fear of motor burn-out.
How do you trip electrical circuit breaker in normal working condition?
One way is to create a current overload deliberately i.e. run two two high-powered electrical appliances (such as, say, a 12 amp vacuum cleaner and a 2 kilowatt electric kettle) together on a circuit that is protected by a 15 or 20 amp circuit breaker. Or create a short circuit.
How overload relay works?
An overload relay is fundamentally a board that protects the relay from overloads. It works on the science of being an AC inductor..
What caues LCD tv to trip off?
The power overload is what causes the LCD television to trip off.
What is the function of an LBB relay?
A local breaker backup relay is used to check the operation of distribution circuit breakers and to trip the feeder circuit breaker if the distribution circuit breaker fails to trip on an overload.
What is the cause of the compressor if not trip to its overload?
What is the cause of a compressor if not trip to its overload
What is short to ground?
A short to ground means there is very little or no resistance between some electrical device and ground. A "dead short" would be no resistance at all. This causes very high current which blows fuses and causes overload protection devices to trip out.
How moeller's overload relay works?
Moeller's overload relay works by monitoring the current flowing through a motor. If the current exceeds a set value for a period of time, the relay will trip and disconnect power to the motor, protecting it from damage due to overheating. This helps prevent the motor from drawing too much current for an extended period, which could be harmful.
What is a over load relay?
they are designed to meet the special protective length of time it will take for a relay to come to an overload condition my answer is :OLR is a device which is used for protection according to the set range beyond the specified set range it will trip
What are breakers?
A breaker is a device that is used to connect and disconnect the buss bars of an electrical panel to the feed end of wires that feed an electrical load. The function of a breaker is to protect the wires from an overload by the use of an internal thermal trip, and to protect the load and wires from a short circuit by use of an internal magnetic trip.
What is the difference between overload trip and over current trip. if there is an overload trip the current will be raised above the set point?
An overload trip is due to too much load on a circuit (for example, my wife running a hair dryer and portable heater on the same outlet). An over current trip is the same thing, but it can also refer to an actual fault condition where conductors have come in contact with eachother/shorted.
What is master trip relay?
its trip the master elements
What will happen to electrical devices if overloaded?
An overload condition is demanding more current than can be supplied. This could trip a breaker, blow a fuse or possibly destroy a device that is drawing too much current.
Overload Trip Class - What does it really mean?
Quite often we here of applications in which the motor protection/overload relay 'trips' during motor starting. The remedial action taken by many when faced with this problem is to select and install a replacement overload relay, generally one that provides a higher 'Trip Class' setting, for example, Trip Class 20 in lieu of the standard Trip Class 10.Note: The appears to be a general misconception in industry that Overload Trip Class relates directly to the starting time of a machine. This is not the case.All due care must be taken when selecting a protection relay offering higher Trip Class, as this can result in under protection and subsequent failure of the motor.To select an overload relay with a more suitable trip class, you must in the first instance obtain data relating to the motor's thermal withstand capabilities. That is, you need to know how many seconds (from cold condition) the motor can the sustain Locked Rotor Current before it is compromised.This information is readily available from most leading manufacturers of motors and is generally provided in one of two formats.a) Specific values for Locked Rotor Current and maximum Locked Rotor Time (from 'cold condition' ) are given.b) A Motor Thermal Withstand Curve is provided.With this information available to you, you can refer to the tables given in IEC 60947 to identify the most appropriate Overload Trip Class. This is defined as the one that provides a trip curve as close as possible to but below the overload curve of the motor. Adopting this process will ensure nuisance tripping is minimised and that the motor is adequately protected at all times.Note: If the above processes are adopted but the trip conditions continue, there are 4 possible causes.1. The motor (and overload relay) are not given sufficient time to cool between starts.2. Assuming reduced voltage start (star/delta, auto-transformer, primary resistance, soft start etc., the motor is not delivering torque sufficient to accelerate the connected load to speed. That is the starting current and starting time under RVS conditions exceeds that permissible by the overload curve.3. A more advanced protection strategy such as motor thermal modelling may be required. Motor thermal modelling allows the user to 'match' the curves of the protection device to the connected motor. This is of particular advantage when the motors thermal withstand capabilities and the start condition (starting current and starting time) fall between two curves defined by standard overload trip classes.4. The motor is simply too small for the application.Put simply, the most appropriate protection strategy is the one that allows the motor to be fully utilised without nuisance tripping or fear of motor burn-out.
