Product Description; Operating Principle; Brake Design - Kendrion EEX Series Operating Instructions Manual

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 utilized 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 brake (brake torque) is reliably transmitted to the
machine (motor). Explosion-protected spring-applied single-disc brakes are characterized 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.

2.2 Brake design

The solenoid housing (1.1) of the spring-applied single-disc brake accommodates the firmly fitted field coil
(1.2) with wire leads. The wire leads are connected to the terminal block (19) inside the junction box (25). The
flange (3) and friction plate (33) are screwed to the solenoid housing (1.1) by means of socket head cap screws
(22). The solenoid housing (1.1) is pressure-sealed by a cover (7) that is attached with socket head cap screws
(20). Owing to the spring force generated by the compression springs (4 & 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 form 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 adjust the air gap 's'. The customer-specific
connecting cable can be introduced into the junction box (25) through a cable gland (30) (M20x1.5). When AC
voltage is applied to the built-in bridge rectifier of the spring-applied single-disc brake, the force of the
electromagnetic field thus generated counteracts the spring force. The armature (2) is released and the braking
action is neutralized. 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 & 12) and with
a microswitch (13) . The microswitch (13) is provided to prevent machine (e.g. motor) start-up before the brake
1)
has been released. The four (2x2) thermoswitches (11 & 12) are connected in series with the microswitch (13).
They 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) so that the hand release can be installed. The hand release (29)
the brake to be released manually (e.g. in case of power failure).
Brake types with microswitch.
1)
Brake types with hand release.
2)
Operating Instructions BA 76..G..B00 // Last updated: 13/03/2020 // Page 7 of 34
allows
2)