Warner Electric CBC-750 User Manual

CBC-750 Series Clutch/Brake Controls

P-270
819-0494

Installation & Operating Instructions

Introduction

Warner Electric’s CBC-750 Series of Constant
Current Overexcitation Clutch-Brake Controls
are solid-state electronic controls designed to
increase the cycle rate capabilities and accuracies
of electromagnetic clutches and brakes. The controls
accomplish this by sending a momentary high
voltage overexcitation spike to the clutch and/or
brake magnetic coil to build a high density magnetic
flux field almost instantaneously. By using overexci­tation, the response time is reduced as dramatically
as performance is increased. For example, the
current build up time of a 5 inch, 6 volt magnet is
reduced from 84 milliseconds to 2 milliseconds.

The CBC-750 user selects either 120, 220, or 240 VAC
operation at the time of installation. Models with 6
volt, 24 volt, or 90 volt clutches and brakes are
available.

LED indicators on the faceplate of each control
tell the user the status of input signals, output
activation and any auxiliary inputs. A reset switch
resets the output should a short be detected.
Remote torque adjust potentiometer inputs are also
provided. Appropriate current range for each size
clutch or brake is selected by a dip switch. Constant
current for each level is assured by the control’s
design

The CBC-750 printed circuit
board and control panel are
shown here. The seven individual
function switches and two range
switches evident in this photo
are detailed in Figure 8, page 10.

Releasing the lock pins and lifting the
top cover reveals the CBC-750’s lower
level where wire connections are
made. Schematic versions of these
terminal boards are found in this
manual on pages 8-10.

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Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . 3

Technical Specifications . . . . . . . . . . . . . . . . . . . 4

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

System Wiring

Wiring Precautions . . . . . . . . . . . . . . . . . . . . . 6

AC Input Power. . . . . . . . . . . . . . . . . . . . . . . . 7

Clutch-Brake Wiring . . . . . . . . . . . . . . . . . . . . 7

Switching Inputs . . . . . . . . . . . . . . . . . . . . . . 8

Auxiliary Outputs . . . . . . . . . . . . . . . . . . . . . . 9

Remote Torque Adjust Potentiometers. . . . . 9

System Start-Up. . . . . . . . . . . . . . . . . . . . . . . . . 11

System Troubleshooting . . . . . . . . . . . . . . . . . . 14

Replacement Parts Listing . . . . . . . . . . . . . . . . 16

Failure to follow these instructions
may result in product damage, equipment damage,
and serious or fatal injury to personnel.

Theory Of Operation

The CBC-750 Series of controls will operate all
Warner Electric clutches and brakes with the
exception of the 1525 HT. Two devices may be
operated from the control; however, only one
device is energized at a time.

The CBC-750’s operate from either 120, 220, or 240
VAC, 50 or 60 Hertz, line voltage. Input voltage is
switch selectable on the Terminal Block Board. A
transformer converts the AC input line voltage to
the three different voltage levels required for the
controls’ internal functioning.

Warranty . . . . . . . . . . . . . . . . . . . . . . . . Back Page

LIST OF FIGURES

Figure #

1 Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 C/B and Power Terminal Connection . . . . . . . . 7

3 AC Selector Switch. . . . . . . . . . . . . . . . . . . . . . . 7

4 I/O Terminal Connection . . . . . . . . . . . . . . . . . . 8

5 Auxiliary Connection . . . . . . . . . . . . . . . . . . . . . 9

6 Remote Potentiometer Connection . . . . . . . . . 9

7 Terminal Board Overview - Inside . . . . . . . . . 10

8 Main Board Switches - Black Switches . . . . . 10

9 I/O Relationships . . . . . . . . . . . . . . . . . . . . . . . 12

The control logic circuits operate from a regulated
12 VDC supply, which can also provide output for
external sensor connections via the terminal strip. A
filtered, unregulated supply provides the necessary
voltages for operation of the over-excitation circuits
as follows:

CBC-750-6: 75 VDC
CBC-750-24 and -90: 240 VDC

These voltages vary within the tolerance limits
necessary to maintain steady state currents.

Normally, a brake operating alone is connected to
Channel 1 output and the clutch is connected to the
Channel 2 output when a combination clutch and
brake is used. Other connections are possible.
A green LED located on the control faceplate
illuminates when the adjacent channel is active.
The steady state output to the clutch and brake is
adjusted by either the torque adjust potentiometers
on the control faceplate or optional external torque
adjust potentiometers. A switch on the main logic
board selects local or remote torque adjust.

Short circuit protection is provided on both output
channels. In case of a short circuit, a red LED
indicator illuminates on the control faceplate for
the output channel affected. Activation of the short
circuit scheme turns the output off until the short is
cleared and the reset pushbutton is activated.

Input switching via opto-isolated input circuits allow
for a variety of interface configurations and make
the control PC compatible in all respects. This
means that switching can be accomplished with
either AC or DC signals as well as electromechanical
contact closures.

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A switch on the main logic board selects level
control switching on the Channel 2 input or pulse
control input switching on both Channels 1 and 2
inputs.

The following is a brief description of how the
system controls outputs:

1. When an input switches on a given channel,
the previous “on” channel switches off. But
this does not happen instantly. Current in the
channel being de-activated is monitored until
it reaches approximately 10% of its steady
state on value. Then the channel being activat­ed is switched on. Automatic torque overlap
protection is achieved by monitoring the
decay current in the channel being de-activat­ed. Current monitoring eliminates the need for

adjustment potentiometers for set-up.

Technical Specifications

Input Power: 120, 220. or 240VAC, ±10%

50/60 Hz single Phase, 350
VA Max.

Output Pulse width modulated full
(Clutch-Brake): wave rectified DC constant

current, switch selectable

ranges

CBC-750-6: Range .900 to

4.340A
CBC-750-24: Range .204 to

1.175A
CBC-750-90: Range .060 to
.310A

Output 12 VDC ±.6 VDC, 250 mA
(Auxiliary): Max.

2. Overexcitation current is monitored on the
output channel being switched on.
Overexcitation
current is twice steady state current in the
CBC-750-90 and three times it in the CBC-750­6
and -24.

3. Once the overexcitation current level is
reached, it is turned off and steady state
holding current is applied to the magnet or
field coil.

This sequence occurs for both channels for either
level of pulse input switching.

Additional input functions are also incorporated into
the control to provide versatility. These include:

• Channel 1 and Channel 2 input inhibit which
inhibits the inputs when activated.

• Output inhibit which de-activates both output
channels on activation.

• A Channel 2 override input which applies full
output current to the Channel 1 load when
activated.

Terminal strip connections for power inputs and
outputs and auxiliary functions are located in the
lower housing of the control. Conduit entrances
are provided in the enclosure. Auxiliary optoisolated
outputs are provided for wiring remote status
monitoring indicators. this allows the user to
monitor control status when the control is remotely
mounted in the machine.

Ambient 0°f to +113°F (-18°C to
Temperature +45°C) with cover installed
Range: 0°F to +140°F (-18°C to

+60°C) with cover removed

Steady State Via front panel potentiome­Current Adjust: ters or remote potentio-

meters when operated in
remote mode

Remote Current Via customer supplied
Adjust: potentiometers

5K ohm ±10%, 1/4 watt
minimum

Overexcitation CBC-750-6: 75VDC Nominal
Voltage: CBC-750-24: 240VDC

Nominal
CBC-750-90: 240VDC
Nominal

Circuit Internal short circuit protection
Protection: on each output channel

Fusing: AC input line: 2A Slo-Blo, 250V

OEX Supply:
CBC-790-6: 10A-32V Slo-Blo
CBC-750-24: 5A-250V Slo-Blo
CBC-750-90: 1A-250V Slo-Blo

Auxiliary Opto-isolated NPN transistors,
Indicator 24VDC maximum applied volt­age, Outputs: 20 mA maximum

current, series connected diode
for reverse polarity protection

Control Opto-isolated, 10VDC @ 10 mA
Inputs: nominal to 30VDC @ 35 mA

nominal sinking or sourcing,
24VAC, 50/60 Hz @ 22 mA
nominal,

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120VAC, 50/60 Hz @ mA
nominal

Maximum Off < 2 mA (Inputs)
State Leakage:

Internal 8 selector switches which set
Adjustments: control operating modes, two 5

range dip switches which select
output current levels

Wiring 5 conduit entrances provided:
Entrance: • 2 openings for 3/4” conduit

• 3 openings for 1/2” conduit

Enclosure: Rated NEMA 1 with optional

cover installed

Sample

Check off each step when completed.

Refer to Figure 1, Page 6, for dimensional data and
mounting hole locations.

1. Pick a suitable location for mounting the
control based on application requirements.

2. Open the control by pulling up on the two
plastic pin connectors that hold the main
board assembly to the lower chassis
assembly.

3. Using the dimensional data in Figure 1, Page
6, mark and drill four (4) mounting holes using
a #21 drill. Tap the four (4) holes using a
#10-32 tap.

CBC 750 Maximum Current by Dip Switch

Installation

This installation and operations manual has been
arranged for the systematic installation and startup
of your Warner electric clutch-brake control system.
To achieve the best possible results, check off each
completed step in the space provided before pro­ceeding to the next step.

Nominal

Voltage

6 0.910 2.350 3.183 3.760 4.340

24 0.227 0.641 0.881 0.940 1.175

90 0.060 0.176 0.256 0.282 0.310

1 2 3 4 5

Switch Setting

4. Start the top two (2) screws in the mounting
holes but do not tighten. Leave sufficient
space between the mounting surface and the
screw heads to mount the control.

5. Carefully slide the large slots of the top two
(2) mounting screw holes in the control
chassis over the heads of the mounting screws
already installed. Slide the control all the way
down on the screws.

Note: If the slots will not fit over the screw

heads, the two mounting screws must
be turned out (CCW) to increase
clearance before the control can be
mounted.

6. With the control chassis held firmly in place,
start the bottom two mounting screws into
their mounting holes. The ribbon connector
may have to be disconnected from the upper
terminal board to start the lower left hand
screw. Do not tighten the screws yet.

7. Line up the control squarely and tighten all
four mounting screws securely. Reconnect the
ribbon connector.

Note: If the control is mounted inside a control

enclosure and wires enter the control without
conduit, use plastic bushings to protect wires
entering the conduit entrance holes.

This completes the mounting installation of the
CBC-750 control chassis. Proceed to the wiring
section for control wiring information.

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