KBIC & KBMM Low Voltage Motor Modification

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
1 WATT

 

 

10 KOHM
1/4 WATT

150 OHM
1/4 WATT

7.5 VOLT
1N4737A

15 VOLT
1N4744A

48

24

KBMM-4824M

1 KOHM
2 WATT

 

 

22 KOHM
1/4 WATT

150 OHM
1/4 WATT

7.5 VOLT
1N4737A

15 VOLT
1N4744A

60 - 70

48

KBMM-7048M

1.8 KOHM
3 WATT

 

 

30 KOHM
1/4 WATT

150 OHM
1/4 WATT

7.5 VOLT
1N4737A

15 VOLT
1N4744A

24

12

KBIC-2412M

 

390 OHM
2 WATT

18 KOHM
1/4 WATT

 

150 OHM
1/4 WATT

7.5 VOLT
1N4737A

15 VOLT
1N4744A

36

24

KBIC-3624M

 

470 OHM
1 WATT

22 KOHM
1/4 WATT

 

150 OHM
1/4 WATT

7.5 VOLT
1N4737A

15 VOLT
1N4744A

48

24

KBIC-4824M

 

1 KOHM
2 WATT

27 KOHM
1/4 WATT

 

150 OHM
1/4 WATT

7.5 VOLT
1N4737A

15 VOLT
1N4744A

60 - 70

48

KBIC-7048M

 

1.8 KOHM
3 WATT

47 KOHM
1/4 WATT

 

150 OHM
1/4 WATT

7.5 VOLT
1N4737A

15 VOLT
1N4744A

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.

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