- Settore: Electrical equipment
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A ratio of a one-minute meggar test (see Meggar Test) to ten-minute meggar test. Used to detect contaminants in winding insulation done typically on high voltage, V.P.I. motors which are tested by water immersion.
Industry:Electrical equipment
Two or three-phase induction motors have their windings, one for each phase, evenly divided by the same number of electrical degrees. Reversal of the two-phase motor is accomplished by reversing the current through either winding. Reversal of a three-phase motor is accomplished by interchanging any two of its connections to the line. Polyphase motors are used where a polyphase (3-phase) power supply is available and is limited primarily to industrial applications.
Starting and reversing torque characteristics of polyphase motors are exceptionally good. This is due to the fact that the different windings are identical and, unlike the capacitor motor, the currents are balanced. They have an ideal phase relation which results in a true rotating field over the full range of operation from locked rotor to full speed.
Industry:Electrical equipment
Identifies the type of power supply providing power to a DC motor. Frequency, voltage, and type of rectifier configuration.
Industry:Electrical equipment
A measurement of the time phase difference between the voltage and current in an AC circuit. It is represented by the cosine of the angle of this phase difference. For an angle of 0 degrees, the power factor is 100% and the volt/amperes of the circuit are equal to the watts. (This is the ideal and an unrealistic situation.) Power factor is the ratio of Real Power-KW to total KVA or the ratio of actual power (watts) to apparent power (volt-amperes).
Industry:Electrical equipment
A relay, the principal function of which is to protect service from interruption, or to prevent or limit damage to apparatus.
Industry:Electrical equipment
The characteristic of a coil, when connected to alternating current, which causes the current to lag the voltage in time phase. The current wave reaches its peak later than the voltage wave reaches its peak.
Industry:Electrical equipment
A device that is operative by a variation in the conditions of one electric circuit to effect the operation of other devices in the same or another electric circuit.
Industry:Electrical equipment
The degree of obstacle presented by a material to the flow of electric current is known as resistance and is measured in ohms.
Industry:Electrical equipment
The rotating member of an induction motor made up of stacked laminations. A shaft running through the center and a squirrel cage made in most cases of aluminum which holds the laminations together and act as a conductor for the induced magnetic field. The squirrel cage is made by casting molten aluminum into the slots cut into each lamination.
Industry:Electrical equipment
A defect in a winding which causes part of the normal electrical circuit to be bypassed. This frequently results in reducing the resistance or impedance to such an extent as to cause overheating of the winding, and subsequent burnout.
Industry:Electrical equipment
