From time to time our customers have had low voltage speed control requirements, and have attempted to run low voltage DC motors using KB drives by simply decreasing the maximum speed adjustment on the drive. This procedure is usually unsuccessful because of the manner in which an SCR Drive controls the output voltage. There is however, a procedure for modifying KBIC and KBMM drives to allow them to reliably run a low voltage DC motor. The table below will indicate which components on the drives need to be replaced with different values, and what AC input voltage will need to be supplied to the drive.
|
AC Input Voltage |
DC Output Voltage |
Control Model |
Resistors |
Zener Diodes |
|||||
|
|
|
|
R17 |
R17A |
R19 |
R19A |
R39 |
Z1 |
Z2 |
|
36 |
24 |
KBMM-3624M |
470 OHM |
|
|
10 KOHM |
150 OHM |
7.5 VOLT |
15 VOLT |
|
48 |
24 |
KBMM-4824M |
1 KOHM |
|
|
22 KOHM |
150 OHM |
7.5 VOLT |
15 VOLT |
|
60 - 70 |
48 |
KBMM-7048M |
1.8 KOHM |
|
|
30 KOHM |
150 OHM |
7.5 VOLT |
15 VOLT |
|
24 |
12 |
KBIC-2412M |
|
390 OHM |
18 KOHM |
|
150 OHM |
7.5 VOLT |
15 VOLT |
|
36 |
24 |
KBIC-3624M |
|
470 OHM |
22 KOHM |
|
150 OHM |
7.5 VOLT |
15 VOLT |
|
48 |
24 |
KBIC-4824M |
|
1 KOHM |
27 KOHM |
|
150 OHM |
7.5 VOLT |
15 VOLT |
|
60 - 70 |
48 |
KBIC-7048M |
|
1.8 KOHM |
47 KOHM |
|
150 OHM |
7.5 VOLT |
15 VOLT |
KBIC and KBMM drives with these modifications already installed and tested can be ordered directly from Transbearco Limited or Transbearco Industriel. Please order using the Control Model Number shown above.