Delta Tau GEO BRICK DRIVE Benutzerhandbuch
Geo Brick Drive User Manual
Pinouts and Software Setup
159
Required Bus Voltage for Speed and Torque
For a required motor Speed, and continuous Torque, the minimum DC Bus Voltage (V
DC
) can be
estimated by looking at the equivalent single phase circuit:
BEMF
R
L
+
-
+
-
Motor
The vector sum of back EMF, voltage across resistor and inductor should be less than
6
/
V
DC
.
For a Rotary Motor:
6
V
M
π
2
3
K
60
R
R
K
T
K
T
L
π
2
N
60
R
V
V
V
DC
derate
2
t
RPM
p
t
M
2
t
M
p
p
RPM
2
BEMF
R
2
L
Where:
V
L
: Voltage Across equivalent inductor
V
R
: Voltage Across equivalent resistor
V
BEMF
: Back electromotive force voltage
R
RPM
: Required Motor Speed [rpm]
N
P
: Number of pole pairs
L
P
: Phase Inductance [H]
R
P
: Phase Resistance [Ω]
T
M
: Required Continuous Torque [N.M]
K
T
: Motor Torque Constant RMS [N.M/A]
M
derate
: De-rate parameter (typically 0.8)
For a Linear Motor:
6
V
M
3
K
D
V
R
K
F
K
F
L
D
V
V
V
V
DC
derate
2
t
pitch
motor
p
t
M
2
t
M
p
pitch
motor
2
BEMF
R
2
L
Where:
V
L
: Voltage across equivalent inductor
V
R
: Voltage across equivalent resistor
V
BEMF
: Back electromotive Force voltage
V
motor
: Required Motor Speed [m/s]
M
derate
: De-rate parameter (typically 0.8)
L
P
: Phase Inductance [H]
R
P
: Phase Resistance [Ω]
F
M
: Required Motor Force RMS [N]
K
t
: Motor Force Constant RMS [N/A]
D
Pitch
: Magnetic Pitch [m]
Example:
An application requires running a motor at 500 RPM with a continuous torque of 30 N.M. The motor
specs are as follow:
10mH
L
p
,
2Ohm
R
p
,
16
N
p
,
ps
2.187Nm/Am
K
t
Using the equation above, a minimum bus of 233 VDC (~165VAC) is necessary to achieve the speed and
torque requirements.
torque requirements.