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What would happen to a three phase motor if two of the three phases are lost?
Wiki User
∙ 12y ago
The motor will keep on running for a while but the current will rise on the other two phases and the overload relay will fall out, if its properly set and the motor will stop if the overload relay is set to high the motor will burn out
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in the start Motor will start to shake the if there is no protection devices for over-load on the motor it will simple explode:)
I have a personal experment on that.
Wiki User
∙ 14y ago
Wiki User
∙ 12y agoIn general a 3-phase motor must have all 3 phases continuously available to run correctly. Loss of one or two phases will result in a very high current being drawn on the remaining one or two phase windings. These windings will overheat. If left in this condition the windings will burn out destroying the motor. How long this will take depends on the individual motor and the load it is driving at the time. Typically a minute or so is sufficient to burn out the windings. Any significant motor (e.g. a water pump such as used for a swimming pool) should always be protected by a special switch which will cut the power completely if one or more phases are lost. Such a switch will normally cost about 1/10th the cost of the pump it protects and is thus a very good investment.
Wiki User
∙ 13y agoThe overload protection on the other two legs should sense the rise in current when one leg fails and drop out the motor's contactor. This disconnects the faulty motor from the supply voltage.
Wiki User
∙ 12y agoThe overload protection system of the motor should activate immediatly to save the motor from burning.
Wiki User
∙ 10y agoIf one phase fails in a three phase system it will cause the voltage to drop.
Wiki User
∙ 15y agoThat depends. If it simply fails, the transformer ceases to work, to produce. If something causes one phase to short, it can cause a fire.
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What should you do if a three phase motor or compressor is not rotating in the correct direction?
If your three phase motor runs backward, you have two phases swapped. double check a, b and c phase to find which ones are misplaced.
What does the phases on a nameplate of a motor mean?
On a three phase motor, the phases give you direction for how to hook the motor up to make it spin one direction vs. the other. If you hook up such a motor blindly with all three phases, it may spin in the opposite direction you want; to fix, you swap any two of the three phase connections.
Why motor burn at single phasing?
A 3-phase motor will not run on single-phase power or if one of the three phases is disconnected. If the motor is not running, there is no back-EMF generated in the coils, and they draw excessive current, thus overheating.
Can a 3 phase motor be converted into a single phase motor?
A three-phase motor will not start if one or two phases aren't connected. If while running one or two phases "drop out", it will continue to run for awhile, but will eventually burn out, unless connected to a motor saver.
Why three phase motors are self starting?
Because the three phases are 120 degrees apart which kind of gives a "rotational magnetic field" as apposed to a two phase motor (your common 220 volt motor) where the phases are 180 degrees apart and the magnetic field opposes itself until the motor is spinning.
Theory for brake test on three phase induction motor?
why three phase induction motor is delta connected
What will happen if winding resistances of a motor are different?
The motor will pull different amounts of power on the different phases, which will result in not operating smoothly for three phase motors.
How do you use a one phase motor in place of a three phase motor?
To use a single/one phase motor instead of a three phase motor is possible if you have a three phase power supply as you will only need to tap one of the three phases together with neutral and an earthwire, however to use a three phase motor instead of a single phase will require the provision of three phase power supply.
What should you do if a three phase motor or compressor is not rotating in the correct direction?
If your three phase motor runs backward, you have two phases swapped. double check a, b and c phase to find which ones are misplaced.
What does the phases on a nameplate of a motor mean?
On a three phase motor, the phases give you direction for how to hook the motor up to make it spin one direction vs. the other. If you hook up such a motor blindly with all three phases, it may spin in the opposite direction you want; to fix, you swap any two of the three phase connections.
What are the three phases of drug effects?
There are three phases of drug effects. These three phases are the administration phase, active phase, and the metabolism phase.
Why motor burn at single phasing?
A 3-phase motor will not run on single-phase power or if one of the three phases is disconnected. If the motor is not running, there is no back-EMF generated in the coils, and they draw excessive current, thus overheating.
Is three phase induction motor continue running when any of the two phase is disconnected?
This question doesn't really make any sense - any of the two phase? A three phase induction motor requires 3 phases to start - if a single phase is lost while the motor is already running then yes the motor will continue to run. A three phase motor will not start if it is missing a phase.
Can a 3 phase motor be converted into a single phase motor?
A three-phase motor will not start if one or two phases aren't connected. If while running one or two phases "drop out", it will continue to run for awhile, but will eventually burn out, unless connected to a motor saver.
Can a three phase motor work on single phase power with out burning up?
A three phase motor will not operate on single phase. The motor will run on two phases but will not start. Motors running on just two phases is called single phasing. The line current of the two legs will go high and it is this factor that the motor controller uses to trip the contactor to open the circuit and isolate the motor from the power source.
Why three phase motor run in reverse even if it is not wired to run in reverse direction?
If a three phase motor in running in reverse, then one of the phases is reversed, plain and simple. If the wiring is correct at the motor, perhaps the phase reversal occurred someplace else.
Why three phase motors are self starting?
Because the three phases are 120 degrees apart which kind of gives a "rotational magnetic field" as apposed to a two phase motor (your common 220 volt motor) where the phases are 180 degrees apart and the magnetic field opposes itself until the motor is spinning.
