1.In two wattmeter method if one wattmeter shows Negative
reading then wat is reason?
2.Wat is the reason for low voltage in houses?
3.Wat is meant by current and voltage? wat is difference
between the two?
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two watt meter method is used in measurement of power under un balanced condition.there are two reasons for - ve value
1). if load consist of more inductivd or capacive load with negligible resistive then it will show _ve value .pf angle is more than 65 deg
. in case of induction motor no load test one of the watt meter will indicate _ve because no load pf is 0.2 lag pf angle is nearer to 75 deg
2).reverse. connections of current coil
| Is This Answer Correct ? | 98 Yes | 6 No |
Answer / max
1)hmm exacly opp
that means pf of load is less than 0.5 but greater than 0
2)load unbalance inductive load(?)
3)voltage -cause n current -effect
| Is This Answer Correct ? | 49 Yes | 20 No |
Answer / sanjoy
5.Yes. It’s possible one wattmeter may indicate a negative value. One Wattmeter will read negative watts if the power factor goes below 0.5 .
| Is This Answer Correct ? | 24 Yes | 4 No |
Answer / nitin banegaon
its sooo simlpe. when induction motor is on load then the no load current will have two components one is active/load component and other magnetizing component. Magnetizing component is for creating magnetic field to spin the motor which is independent of load current and it lags behind the voltage by 90. Initially on load, current is so small which is normally is in phase with applied voltage. So on no load circuit is inductive. So power factor is small nearly 0.2 to 0.4.
| Is This Answer Correct ? | 8 Yes | 1 No |
Answer / syam kumar
2.reasion due to low voltage in houses is, in our street
poles we have generally 3 phase wires and 1 neutral
wire.every house connected to 1 phase and neutral wire.if
more number of houses connected by same phase then those
are effected from this low voltage problem.so some houses
will have power and some houses effected from this low
voltage. so if we connect equal distribution to all phases
this effect is reduced. this connection will given by our
linemen.
3.flow of charge is current
and potential difference between any two points in a
conductor is called voltage.
voltage and current are combinational.
| Is This Answer Correct ? | 6 Yes | 4 No |
Answer / kd
1.power flow is in the reverse direction
2. Power factor is less than 0.5
Thanks !
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / james nyoro
1;phase angle is greater than 90 degrees cos 90=0 cos-in
=math error
2;reverse connection of current coil
| Is This Answer Correct ? | 2 Yes | 7 No |
Answer / kaushik patel
But how measure it negative value. That is below in 0. And the pointer go to below zero and below zero not mention calibration then how measure it?
| Is This Answer Correct ? | 0 Yes | 5 No |
Answer / vikas
because in wattmeter there r two internal winding i.e., m
and c which need to be short . if ther are not short then
one wattmeter shows negative value.
| Is This Answer Correct ? | 5 Yes | 44 No |
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