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A magnetic starter has a contactor and an overload relay, which will open the control voltage to the starter coil if it detects an overload on a motor. [1] [2] The overload relay opens a set of contacts that are wired in series with the supply to the contactor feeding the motor. The characteristics of the heaters can be matched to the motor so ...
This induced current creates an auxiliary magnetic flux which is 90 degrees out of phase from the magnetic flux created by the primary coil. [ 1 ] Frager spire or shading coil's purpose is to provide sizeable phase-shifted magnetic field (in blue) to keep the contactor on when the main coil flux (in red) passes through zero, avoiding unwanted ...
The magnetic blowouts in the pictured Albright contactor (which is designed for DC currents) more than double the current the contactor can break, increasing it from 600 A to 1,500 A. Sometimes an economizer circuit is also installed to reduce the power required to keep a contactor closed; an auxiliary contact reduces coil current after the ...
A mercury relay (mercury displacement relay, mercury contactor) is a relay that uses mercury as the switching element. They are used as high-current switches or contactors , where contact erosion from constant cycling would be a problem for conventional relay contacts.
Digital Soft Starter. Whenever the armature of an electric motor is moving, both the motor action and generator action are occurring simultaneously; the electromagnetic force produced by generator action opposes the desired motor action and effectively creates a variable motor resistance which increases with motor speed.
Pole means magnetic pole, and poles always come in pairs, usually referred to as "North" and "south." Poles may be physical objects in fixed places, or poles may be virtual objects moving as the machine operates. A pole may be a single piece of magnetic material, or a pole may be distributed over multiple teeth.
A shaded-pole motor is a motor, in which the auxiliary winding is composed of a copper ring or bar surrounding a portion of each pole to produce a weakly rotating magnetic field. [2] When single phase AC supply is applied to the stator winding, due to shading provided to the poles, a rotating magnetic field is generated.
The magnetic field is often created by a current-carrying coil of wire around the core. The use of a magnetic core can increase the strength of magnetic field in an electromagnetic coil by a factor of several hundred times what it would be without the core. However, magnetic cores have side effects which must be taken into account.