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The only time a motor should go into a locked rotor condition is if the motors connected load jams causing the motor to stop turning. At this point if the motor control circuitry is sized to the motor's full load amperage, the high rise in current will trip the motor off line.
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LRA is 134 AMPS. what size breaker should be used?
LRA (locked rotor amps) is not used to calculate the breaker size. Breaker's are used to protect the size of the conductor that is connected to it. Motor calculations are based on the motor's FLA (full load amps).Conductor size is 125% of the motor's FLA.Breaker size is 250% of the motor's FLA.This is the only occasion when the breaker is sized larger that the conductors maximum amperage rating. This is due to the motor drawing up to 300 to 600% of its FLA when starting.If you state the motor's wattage, voltage or amperage this calculation can be calculated here.
How does a DC brushless motor work?
To state it simply, a DC brushless motor is not a DC motor. It is an AC motor with an inverter (or electronic commutator) on the front end to make the AC, so you can use a DC input.
What is Overload Solid State relay?
a relay that detects the amperage the motor is drawing when the motor dwaws too much to drops out the coil voltage to shut down motor and prevent damage
Do 1 phase electric motors need starters?
it depends on the load and size of the motor if the motor has to drive heavy loads from initial state it require more torque, for this we use star-delta starters where load on motor in permissible then we use a DOL starters DOL starters are direct supply feeders to the motor so there is no rule to use a starter. we can use anything to swith the motor. for protection we need a overload relay and you ask for a 1ph motor, i.e maximum 3hp motors are available for less than 2 hp motor you can use a 6amp switch used in household or a 6amp mcb (includes overload). for 3hp a 16 amp switch or a 10amp mcb is more than enough
What is MCC in electrical engineering?
MOTOR CONTROL CENTER. A motor control center consists of one or more vertical metal cabinet sections with power bus and provision for plug-in mounting of individual motor controllers. Very large controllers may be bolted in place but smaller controllers can be unplugged from the cabinet for testing or maintenance. Each motor controller contains a contactor or a solid-state motor controller, overload relays to protect the motor, fuses or a circuit breaker to provide short-circuit protection, and a disconnecting switch to isolate the motor circuit. Three-phase power enters each controller through separable connectors. The motor is wired to terminals in the controller. Motor control centers provide wire ways for field control and power cables. Each motor controller in an MCC can be specified with a range of options such as separate control transformers, pilot lamps, control switches, extra control terminal blocks, various types of bi-metal and solid-state overload protection relays, or various classes of power fuses or types of circuit breakers. A motor control center can either be supplied ready for the customer to connect all field wiring, or can be an engineered assembly with internal control and interlocking wiring to a central control terminal panel board or programmable controller.
What is the problem with a crane motor if it cannot lift a load and makes a heavy humming sound?
It sounds like the motor stalled and the rotor was locked. In this state there is a heavy current draw that can burn the motor out. Hopefully it is protected by overload protection and the heaters should have taken the motor off line. The motor and crane should have been matched together as a unit. Check the mechanical capacity of the crane to make sure that it isn't working outside its lifting capacity. If the crane has a mechanical break on it check and make sure that the break is releasing when the motor starts.
LRA is 134 AMPS. what size breaker should be used?
LRA (locked rotor amps) is not used to calculate the breaker size. Breaker's are used to protect the size of the conductor that is connected to it. Motor calculations are based on the motor's FLA (full load amps).Conductor size is 125% of the motor's FLA.Breaker size is 250% of the motor's FLA.This is the only occasion when the breaker is sized larger that the conductors maximum amperage rating. This is due to the motor drawing up to 300 to 600% of its FLA when starting.If you state the motor's wattage, voltage or amperage this calculation can be calculated here.
How does the centrifugal switch work in a single phase electric motor?
In a single phase electric motor, the centrifugal switch allows the start winding to be energized through the start capacitor when the motor is starting. This gives an out of phase magnetic field that, along with the in phase magnetic field from the run winding, helps the rotor to begin spinning. Once the rotor reaches a certain speed, the centrifugal switch changes state and cuts off the start winding. At that point, the motor continues running only through its run winding, and inertia keeps the rotor properly phase biased relative to the run winding's magnetic field.
Which Indian state is not a land locked?
Orissa
What state has the largest locked harbor?
cali
How does an induction motor start?
The emf induced in the rotor depends upon the rotor frequency which further depends on relative speed between rotor and synchronous speed of rotating magnetic field. The relative speed at the time of starting or standstill is maximum and hence large emf in induced in rotor conductors or winding due to which very high current flows in rotor which is generally 5 to 7 times of the full load or running current of an indication motor. The starting current, sometimes called inrush current will be 8-10 times higher than the motor's rated current because the motor is at rest. When at rest, the motor appears to be a transformer, with it's secondary winding short circuited, i.e. the rotor winding or squirrel cage is a closed circuit. This results in a low impedance to the system voltage and the motor has a "locked rotor" current of typically 6 times full load current, but also up to 8 and sometimes 10 times current. This starting value is independent of any load attached, however, the inertia of the motor and load has to be overcome. This is especially true when the motor is connected to a load, like a conveyor belt with product on it. The larger the inertia, the longer the motor takes to reach full speed. As the motor accelerates, part of the starting current power overcomes this inertia and is conveted to kinetic energy. The remaining power of the starting current heats the rotor, up to possibly 250 deg C for a "long" start (20 seconds!!). During the first couple of cycles of AC current, transient currents make some of the phases have higher assymetrical values, which can cause nuisance tripping of the supply breakers to the motor, when protection settings are too low! Equation for current: I = P / cos phi / ( 1.732 * V), (cos phi can be 0.3 during starting). V (voltage) stays pretty much constant, therefore I (current) must rise (but is limited to the locked rotor value for the specific motor) as P (power) is required to start the motor and to keep it running. Some voltage drop will occur for most power systems during a motor start, thus with a constant locked rotor impedance, the starting current will reduce proportionally. I start = V / 1.732 / Z (locked rotor) for a three phase motor. (Z is fixed) When nearly full running speed is reached, the current drops rapidly to full load current or less, depending on the actual load attached. -Don't forget to recommend Kevlarster if you like this answer!
Why is a three phase induction motor self starting?
A brushless DC motor is self-starting using only one magneto-sensitive element because the motor is of a two-phase type and is provided with a detection device which detects towards which of the two phases the rotor is mainly directed. A presetting circuit compares the detected rotor position with the state of an energizing circuit in order to set this circuit so that the energizing circuit energizes the stator phases for said specific rotor position in such a way that starting of the motor is guaranteed, although initially with an undefined direction of rotation. By presetting the commutating direction of the energizing circuit the rotor subsequently locks onto the field and rotates in the correct direction if it has started in the incorrect direction
What New England state is land locked?
vermont
Does Nevada have oceans?
No. Nevada is a land-locked state.
Is orissa a land locked state?
No, Orissa is not completely landlocked.
Can a person go into a locked garage in Virginia to repo a car and can they move another car by force to get to it?
NO locked anything in any state. CALL a local atorney for state specific advice.
What do you call a state that is surrounded by other states and does not touch water?
That's a land-locked state.
