KB Electronics KBMM-225D - Manual (Page 7)

3 INTRODUCTION
Thank you for purchasing the KBMM™ “Standard of the Industry” full-wave variable speed DC motor control, now
with SMT construction. The control offers the user the ultimate in reliability and performance at an affordable
price. The controls contain a unique patented super-fast Direct-Fed™ current limit circuit that protects the SCR
power bridge against direct shorts 1 . The reliability of the control is further enhanced with the use of high-surge, 25
Amp SCRs, and AC line and armature fusing 2, 3 . The control is designed with KB’s exclusive Plug-In Horsepower
Resistor® 3 , which eliminates the need for recalibrating IR Comp and Current Limit when the control is used on
various horsepower motors. In addition, the rating of the control can be extended to 1.5 HP for controls with 90
Volt DC output and 3 HP for controls with 180 Volt DC output, by the use of KB’s Auxiliary Heat Sink 4 . Models
KBMM-225 and KBMM-225D also allow operation of 90 Volt DC motors when used on 208/230 Volt AC line
input 5 .
The versatility of the control is confirmed by its extensive list of standard features, such as: selectable armature
and tach feedback and adjustment trimpots for minimum speed, maximum speed, current limit, IR compensation,
and linear acceleration and deceleration. The control includes Auto-Inhibit®, which eliminates surging during rapid
AC line switching; pulse transformer triggering, which provides cogless operation at low speed; and superior noise
rejection circuitry, which eliminates false starts and blown SCRs. Enable (normally closed) and Inhibit (normally
open) functions provide electronic switching of control output.
The output voltage of the control is a linear function of the Main Speed Potentiometer rotation. In addition, the
control can be used in a voltage following mode by supplying an isolated analog input signal to Terminals “P2” (+)
and “P1” (-) 6 . The control is compact in size (only 4.30” X 3.64” X 1.25”) and easily replaces all competitive speed
controls. The control is supplied with a 5 k
Ω Main Speed Potentiometer and QD terminals. All models are UL
Listed (USA and Canada) and CE Approved.
Notes: 1. Short circuit protected at motor only. 2. KB Limited Warranty applies. See page 32. 3. Fuses and
Plug-In Horsepower Resistor® supplied separately. See Sections 8 and 9, on pages 20 - 22. 4. Part No. 9861.
See Section 14.1, on page 30. 5. Step-Down operation. 6. If an isolated signal input is not available, or if using a
4 - 20 mA DC signal input, install the optional plug-on SI-6 Signal Isolator (Part No. 9444).
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