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Difference between two quadrant and four quadrant energy meters. ..

J

Jaspreet

Jan 1, 1970
0
Hi,

What i want to know:
I just want to ask a very basic question.
I read it many times that four quadrant energy meters are
bi-directional and two quadrant energy meters are uni-directions (or
ratcheted). I want to know what are these four quadrants ( preferebly
on cartesian chart shown below)and how does a meter operated in these
four quadrants?

4 Quadrant and 2 quadrant action of a motor is described below. But a
meter can't act as a generator. Then why people describe meters as two
quadrant meters and four quadrant meters.

============================================================================
What i know :
In motor/generator operation, the term two quadrant/ four quadrant
comes from the speed vs. torque chart. It is normally a Cartesian
coordinate chart where the +/- speed is the x axis and the torque is
in the +/- y axis. See chart [hopefully intact]

t|
II o| I
r|
q| speed
------------u--------------
e|
III | IV
|
|


Two quadrant means that the motor drive operates between quandrant I
and III. These types of motor can not stop instantly and reverse
directions.

Four quadrant motor drive operate in all four quadrants. These types
of drives can do both "motoring" (I & III) and generating (II & IV).
The motor acts as a generator when its inertia is continues to rotate
it one way when it is in reverse rotation.


-----------------------------------------------------------------

Please explain it in cartesian coardinates, if possible.


Regards,
Jaspreet
 
R

Rene Tschaggelar

Jan 1, 1970
0
Jaspreet said:
Hi,

What i want to know:
I just want to ask a very basic question.
I read it many times that four quadrant energy meters are
bi-directional and two quadrant energy meters are uni-directions (or
ratcheted). I want to know what are these four quadrants ( preferebly
on cartesian chart shown below)and how does a meter operated in these
four quadrants?

4 Quadrant and 2 quadrant action of a motor is described below. But a
meter can't act as a generator. Then why people describe meters as two
quadrant meters and four quadrant meters.

The main difference being that 4 quadrants allows a
motor to be generator. This may be usefull in a lift
when a heavy mass has to be lowered. The braking energy
could be used to generate electricity.

Rene
 
J

John Popelish

Jan 1, 1970
0
Jaspreet said:
Hi,

What i want to know:
I just want to ask a very basic question.
I read it many times that four quadrant energy meters are
bi-directional and two quadrant energy meters are uni-directions (or
ratcheted). I want to know what are these four quadrants ( preferebly
on cartesian chart shown below)and how does a meter operated in these
four quadrants?

4 Quadrant and 2 quadrant action of a motor is described below. But a
meter can't act as a generator. Then why people describe meters as two
quadrant meters and four quadrant meters.

============================================================================
What i know :
In motor/generator operation, the term two quadrant/ four quadrant
comes from the speed vs. torque chart. It is normally a Cartesian
coordinate chart where the +/- speed is the x axis and the torque is
in the +/- y axis. See chart [hopefully intact]

t|
II o| I
r|
q| speed
------------u--------------
e|
III | IV
|
|

Two quadrant means that the motor drive operates between quandrant I
and III. These types of motor can not stop instantly and reverse
directions.

Four quadrant motor drive operate in all four quadrants. These types
of drives can do both "motoring" (I & III) and generating (II & IV).
The motor acts as a generator when its inertia is continues to rotate
it one way when it is in reverse rotation.

-----------------------------------------------------------------

Please explain it in cartesian coardinates, if possible.

Regards,
Jaspreet

The quadrants have to do with the possible signs on torque and
rotation rate. If the torque is positive and the rotation rate is
positive, that is quadrant 1. If the torque and rotation rate are
both negative, that is quadrant 3. In both of these cases, the
product of torque and rotation rate produces a positive value,
indicating power delivery to the shaft. In quadrants 2 and 4, torque
and rotation rate have opposite signs, so their product produces a
negative value of power, indicating receipt of power from the shaft
and generation of electrical power instead of consumption.

A 4 quadrant drive can not only deliver power to the motor in for
either polarity of voltage, it can also accept power from the motor
for either polarity of voltage, and push this power back into the
power lines.
 
G

GPG

Jan 1, 1970
0
Substitute V and I for axes. In two Q the W is negative.
 
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