3.4. Calculation of the nominal current
In order to stepper engine gave maximum torque, but it does not overheat, it is important to specify such technical characteristic as
the rated current.
The greater a current in the motor winding, the greater the torque at the axis. It is important to remember that with an increase a
current flowing through the winding, thermal power released by the motor increases. So the engine could operate for a long time
allocated to thermal power (
) must be less power dissipation. Power dissipation can be calculated on the basis of
documentation on the engine.
Calculation based on the parameters of unipolar full step mode
Power dissipation is equal to
, where R
u
- the resistance of the winding in unipolar mode, I
u
- current through the
winding in unipolar mode, n - the number of simultaneous windings.
Consider, for example,
. The table in the documentation shows that in full step mode simultaneously running two
phase (n = 2) in the unipolar mode, i.e.
. The motor controllers support only bipolar control mode. To switch from a
unipolar to a bipolar mode, connect each phase windings in series, the resistance will increase,
, where R
b
- the resistance
of the series-connected windings in the bipolar control mode.
The motor controllers control algorithm is capable of operating in a microstepping mode and maintains the current so that the first
winding current varies in function
, in the other winding current varies in function
, where I
a
- current amplitude.
Thermal power released two windings at any time
It follows from the foregoing that the
Calculation based on the parameters of bipolar full step mode
Power dissipation is equal to
, where R
b
- the resistance of the winding in bipolar mode, I
u
- current through the winding
in bipolar mode, n - the number of simultaneous windings.
Consider, for example,
. The table in the documentation shows that in full step mode simultaneously running two phase
(n = 2) in the bipolar mode, i.e.
Thermal
power
dissipated
in
the
motor
windings
that
managed
by
motor
controller,
still
is
We obtain the equation equating power
. We find that
The relationship with an rms current
Alternating
current
in
each
motor
winding
can
be
characterized
by
its
rms
value
in
the
period
. Thermal power of one winding is associated with an rms current through it
.
Both windings are identical
. The total thermal power of the engine that is run by control by motor controller controller
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Page 27 / 345
Summary of Contents for 8SMC5-USB
Page 30: ...Linux Page 30 345 Page 30 345 ...
Page 83: ...Connection of magnetic brake to one axis or two axis systems Page 83 345 Page 83 345 ...
Page 87: ...Scheme of buttons connection to the HDB 26 connector Page 87 345 Page 87 345 ...
Page 99: ...Page 99 345 Page 99 345 ...
Page 167: ...Vertical load capacity the maximum vertical load on the stage Page 167 345 Page 167 345 ...
Page 186: ...Click Next Click Continue anyway Page 186 345 Page 186 345 ...
Page 188: ...Page 188 345 Page 188 345 ...
Page 190: ...Page 190 345 Page 190 345 ...
Page 193: ...Page 193 345 Page 193 345 ...
Page 201: ...Select the XILab application in the Programs block Start it Page 201 345 Page 201 345 ...
Page 274: ...7 Files 1 Configuration files 2 Software Page 274 345 Page 274 345 ...
Page 331: ...Motorized Iris Diaphragms 8MID98 Motorized Iris Diaphragm Page 331 345 Page 331 345 ...
Page 338: ...8 Related products 1 Ethernet adapter Page 338 345 Page 338 345 ...
Page 339: ...8 1 Control via Ethernet 1 Overview 2 Administration Page 339 345 Page 339 345 ...