Kendrion Binder Magnete GmbH
Operating Instructions 76 ..P..B00
Last updated: 30 Dec. 2009
Page 5
2. Product description
2.1 Operating
principle
The spring-applied single-disc brake is designed to operate dry. The force generated by an electromagnetic
field is utilised to overcome the braking effect produced by the spring force.
The spring-applied single-disc brake engages in unpowered condition and releases when AC voltage is
applied. The form-fit connection between the friction disc and hub and the connection of the hub with the
machine shaft (e.g. motor shaft) ensure that the torque generated by the spring-applied single-disc brake
(brake torque) is reliably transmitted to the machine (motor). Spring-applied single-disc brakes with firedamp
protection are characterised by the fact that all components that may ignite explosive mixtures are placed in
an enclosure. This enclosure is designed to withstand the specified test pressure in case the mixture
explodes inside the enclosure. It also ensures that mixtures outside the enclosure are not affected by the
explosion. To ensure reliable firedamp protection, the cable entry of the spring-applied single-disc brake is
equipped with a special threaded entry sleeve.
2.2 Structure
The solenoid housing (1.1) of the spring-applied single-disc brake accommodates the firmly fitted field coil
(1.2) with flying leads. The flying leads are connected to the connecting terminal (19) inside the connector
box (25). The flange (3) and friction plate (33) are screwed to the solenoid housing (1.1) by means of
machine screws (22). The cover (7) is fixed to the solenoid housing (1.1) by means of machine screws (20)
to obtain a pressure-sealed assembly. Owing to the spring force generated by the compression springs (4
and 35), the friction disc (5) is pressed over the armature (2) against the friction plate (33) and flange (3) to
generate the braking effect of the spring-applied brake. The friction disc (5) and hub (17), which constitute
the rotating part of the spring-applied brake, are connected with the shaft to be braked. The friction disc (5)
features a square socket and can be moved on the hub (17) in axial direction. Spacer sleeves (6) are
provided to allow the air gap 's' to be adjusted. The customer-specific connecting cable can be fed into the
connector box (25) through a cable entry sleeve (30). When AC voltage is applied to the built-in bridge
rectifier of the spring-applied single-disc brake, the spring force is overcome by the dynamic effect of the
electromagnetic field. This causes the armature (2) to be released and the braking effect to be neutralised.
The shaft to be braked is not exposed to any axial force by the brake. The spring-applied single-disc brake is
equipped with a redundant thermoswitch system (2x2 thermoswitches) (11 and 12) and with a microswitch
(13)
1)
. The microswitch (13) is provided to prevent machine (e.g. motor) start-up before the brake has been
released. The four (2x2) thermoswitches (11 and 12) are connected in series with the microswitch (13) and
interrupt the control circuit of the machine (e.g. motor) as soon as the maximum permitted brake temperature
is exceeded. When using brakes with hand release (29), openings must be provided in the part enclosing the
brake (e.g. fan cover) to allow the hand release lever to be installed. The hand release (29)
2)
allows the
brake to be released manually (e.g. in case of power failure).
1)
brake types with microswitch
2)
brake types with hand release
Key to figures:
1.1 Solenoid housing
13.3 Angle
25
Connector box
1.2 Field coil
13.4 Countersunk screw
26
Cover
2 Armature
13.5
Plate
27 Machine
screw
3 Flange
13.6
Machine
screw
28 Spring
washer
4
Compression spring
13.7 Connecting cable (microswitch) 29
Hand release
5
Friction disc
14
Circlip (outer ring)
29.1 Cam
6
Spacer sleeve
15
Circlip (inner ring)
30
Cable entry sleeve assembly
7
Cover
16
O-ring
30.1 Threaded cable entry sleeve
8
Fixing surface
17
Hub
30.2 Sealing ring
9
Flat seal
18
Deep groove ball bearing
30.3 Machine screw
10
Fixing screw
19
Connecting terminal
30.4 Clamping strap
11
Thermoswitch (2 switches)
20
Machine screw
31
Locknut
12
Thermoswitch (2 switches)
21
Spring washer
32
Machine screw
13
Microswitch
22
Machine screw
33
Friction plate
13.1 Locknut
23 Spring washer
34
Rating plate
13.2 Set screw
24
O-ring
35
Compression spring
36
Duct
