Baldor BC142, Installation And Operation Manual

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INTRODUCTION

Thank you for purchasing the BC141, BC142, or BC142-6 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 exclusive Plug-In Horsepower

Resistor®

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, 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 an Auxiliary Heat Sink

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. Catalog Nos.

BC142 and BC142-6 also allow operation of 90 Volt DC motors when used on 208/230 Volt AC line input

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.

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, 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 rejec-

tion 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” (-). 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 factory installed 25 Amp AC line fuse and 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.

Baldor Limited Warranty applies. See page 32. 

3.

Plug-In

Horsepower Resistor® and Armature Fuse Kit supplied separately. See Sections 8 and 9, on pages

20 - 22. 

4.

Catalog No. BC143. See Section 14.1, on page 30. 

5.

Step-Down operation.

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