LEESON SCR Thyristor Motor Control - Manual (Page 50)

44 Application Notes SPEEDMASTER™ OPERATION MANUAL
Adjustable speeds using potentiometers in
series
Replace the speed adjust potentiometer with a single pole,
multi-position switch, and two or more potentiometers in series,
with a total series resistance of 10K ohms. Figure 22 shows a
connection for fixed high and low speed adjust potentiometers.
CW
S3
S2
S1
CW
5K
OHM
5K
OHM
HIGH
SPEED
LOW
SPEED
Figure 22. Adjustable Fixed Speeds Using
Potentiometers in Series