III.2.3 Adjustment facilities
III.2.3.1 Tachometer potentiometer P1
The potentiometer P1 is used for the fine adjustment of the tachometer. The range of
adjustment is8—75V.
The standard components installed are for tacho voltages of 8V or 75V at a setpoint voltage of
10V and with the potentiometer on the right stop or left stop respectively.
III.2.3.2 Setpoint potentiometer P2
Potentiometer 2 is used as an attenuator for the setpoint input 2.
Turning the pot. to the right increases the speed.
(range of adjustment 0 — 100%)
III.2.3.3 Offset potentiometer P3
The offset potentiometer P3 is used to compensate for error voltages which may be present in
the operational amplifier or the setpoint voltage source (control) at a setpoint = 0V.
Make the adjustment with the transistor controller activated (enabled) and setpoint voltage = 0V
so that the motor is at standstill.
III.2.3.4 AC-GAIN potentiometer P4
The proportional gain of the PI speed controller can be increased by turning P4 to the right (the
control loop becomes stiffer). When the potentiometer is at the left stop, R24 fixes the basic gain
at about 15.
The integral section is fixed by C4 at 150kW x 0.1mF = 15ms. Increasing C4 makes the control
loop slower (softer) . Reducing C4 improves the response of the controller, but increases the
tendency to oscillation. The standard components fitted will only need to be changed in very few
cases.
The setting of P4 is made, while the amplifier is activated and the motor is at standstill (setpoint
voltage = 0 V), by turning it to the right, up to the threshold of oscillation (this can be seen very
clearly on an oscilloscope connected to the current monitors) and then turning it back until it is
clearly below the threshold of oscillation.
R112 limits the gain for the I-section at very low frequencies to about 5000.
C33 limits the P-gain at medium frequencies (1ms time constant).
Page III - 4 Functions and Options Chapter III
Series 04S 12.99 Kollmorgen
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