Mini Maestro User Guide
21
Issue Number: 5
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Adjusting the nominal current
When the nominal current rating of the motor is less than the nominal current of the
drive, it is possible to reduce the maximum value of current produced by the drive by
fitting a RIN resistor. Refer to the following table:
The following equation is used to calculate the value of the RIN resistor:
Where:
I
NOM
= nominal desired current value
I
PEAK
= Drive peak current value
Adjusting speed for operation in armature feedback mode
JUMP.CRA jumper
RKW.CRA resistor
RAI resistor
Armature feedback mode can be used when a tachogenerator is not fitted to the motor.
Speed control is then less precise.
Speed is controlled using the motor voltage as feedback.
Voltage drop due to motor resistance can be compensated by adjusting the value of the
RAI resistor.
1. Connect jumper
JUMP.CRA
to enable operation with armature feedback.
2. Use the following equation to calculate the correct value of RKW resistor:
RKW
=
0.260
x
Vm
x
Ke
motor
Where:
Vm
= Maximum speed in RPM
Ke
motor
= Motor voltage constant (voltage at 1000 RPM)
Calculating the value of the RAI resistor can be difficult since it is a function of the
following:
•
Motor characteristics. (eg. armature resistance and temperature).
•
Brush resistance (changing with wear).
Model
Nominal current
3 / 6
3.0
2.8
2.6
2.4
2.2
1.9
1.7
1.5
1.2
1.1
0.9
7 / 14
7.0
6.5
6.0
5.5
5.0
4.4
4.0
3.4
2.8
2.5
2.2
10 / 20
10
9.3
8.6
7.8
7.0
6.3
5.7
4.9
4.0
3.5
3.1
14 / 28
14
13
12
11
9.9
8.8
8.1
6.8
5.6
4.9
4.3
Value K
Ω
65
30
18
12
8.6
6.8
4.7
3.3
2.7
2.2
RIN
10000 I
NOM
×
(
)Ω
I
PEAK
2 I
NOM
×
(
)
–
[
]
------------------------------------------------------
=
The correct setting of RIN resistor is necessary to prevent damage to motor and risk of
fire in the event of overload.
WARNING
Содержание Mini Maestro DCD60x10/20
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