How is the direction varied?

How is the direction varied?
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A general purpose DC motor can be reversed by changing the polarity of either the armature or the field but not both.
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Related questions

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Last Answer : By changing the phase sequence (from say R-Y-B to R-B-Y)

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Description : How is the speed of a DC motor varied?

Last Answer : To vary the speed of a DC motor we need a constant voltage power supply with a series POT resistor of higher watt rating. A Pulse Width Modulator (PWM) can be used.

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The left hand rule correlates to (a) current, induced e.m.f. and direction of force on a conductor (b) magnetic field, electric field and direction of force on a conductor (c) self induction, mutual induction and direction of force on a conductor (d) current, magnetic field and direction of force on a conductor

Description : The left hand rule correlates to (a) current, induced e.m.f. and direction of force on a conductor (b) magnetic field, electric field and direction of force on a conductor (c) self induction, ... and direction of force on a conductor (d) current, magnetic field and direction of force on a conductor

Last Answer : (d) current, magnetic field and direction of force on a conductor

Fleming's left hand rule is used to find (a) direction of magnetic field due to current carrying conductor (b) direction of flux in a solenoid (c) direction of force on a current carrying conductor in a magnetic field (d) polarity of a magnetic pole

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How can the direction of rotation of an AC motor be reversed?*

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Last Answer : By interchanging any two supply lines.

The direction of induced EMF can be found with the help of -

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If the centre distance of the mating gears having involute teeth is varied within limits, the velocity ratio (A) Increases (B) Decreases (C) Remains unchanged (D) None of these

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In________, the phase of thecarrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant. A) ASKB)PSKC)FSKD)QAM

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In_________, the frequencyof the carrier signal is varied to representdata. Both peak amplitudeand phase remain constant. A) ASK B) PSK C) FSK D) QAM

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In________, the amplitude of the carrier signal is varied to create signal elements. Both frequency and phase remainconstant. A) ASK B) PSK C) FSK D) QAM

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In QAM,both ________ of acarrier frequencyare varied. A) frequencyand amplitude B) phase andfrequency C) amplitudeand phase D) none of the above

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Last Answer : amplitudeand phase

A price fixed by a manufacturer which cannot be varied by a retailer is called ____________ 1. Ad valorem Price 2. Manufacturing price 3. Retailer's price 4. Market Price 5. Administered Price

Description : A price fixed by a manufacturer which cannot be varied by a retailer is called ____________ 1. Ad valorem Price 2. Manufacturing price 3. Retailer's price 4. Market Price 5. Administered Price

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Gradually varied flow in open channel is a/an __________ flow. (A) Steady uniform (B) Steady non-uniform (C) Unsteady uniform (D) Unsteady non-uniform

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Capacity of a rotary gear pump can be varied by (A) Changing the speed of rotation (B) Bleeding air into suction (C) Bypassing liquid from the suction or discharge line (D) All (A), (B) and (C)

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When the flow in an open channel is gradually varied, the flow is said to be (A) Steady uniform flow (B) Steady non-uniform flow (C) Unsteady uniform flow (D) Unsteady non-uniform flow

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Description : Gradually varied flow is (A) Steady uniform (B) Non-steady non-uniform (C) Non-steady uniform (D) Steady non-uniform

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Description : Overland flow drainage on and from the tarmac of an airport invokes, in its design, principles involving : (a) Spatially varied flow without hydraulic jumps (b) Backwater flow (c) ... throughout (d) Attention to rolling flows within spatially varied flows and possibly to moving hydraulic jumps

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Give two reasons why the value of the normalized frequency (V) is varied in single mode stepindex fibers?

Description : Give two reasons why the value of the normalized frequency (V) is varied in single mode stepindex fibers?

Last Answer : To increase performance and reduce losses caused by bending and splicing.

How can field strength be varied in a practical dc generator?

Description : How can field strength be varied in a practical dc generator?

Last Answer : By varying the input voltage to the field coils

What characteristic of a transistor is varied in a semiconductor-reactance modulator?

Description : What characteristic of a transistor is varied in a semiconductor-reactance modulator?

Last Answer : Collector-to-emitter capacitance.

What characteristic of a carrier wave is varied in frequency modulation?

Description : What characteristic of a carrier wave is varied in frequency modulation?

Last Answer : Instantaneous frequency.