HOW IT WORKS
Working Principle - Power-ON Releases, Power-OFF Brakes
Power ON - brake RELEASED
AC motor drives the centrifugal pump impeller.
Hydraulic pressure rises inside the cylinder.
Piston + push rod extend upward, compressing the brake spring.
Brake shoes open - the equipment RUNS.
Power OFF - brake LOCKED
Motor stops, oil pressure disappears.
The ZC buffer spring + rod weight smoothly pull the rod back down.
Brake spring re-clamps the shoes - FAIL-SAFE locked.
Why ZC matters
The extended buffer spring makes the return progressive rather than sudden: no rigid impact, less shock to the lining and lever, and far less vibration on precision conveying lines.
NC (normally-closed) fail-safe chain
Power loss → spring brakes (mechanical, no electronics).
Cable break / contactor trip → spring brakes.
Hydraulic leak / oil loss → pressure drops → spring brakes.
Safety is independent of control voltage - meets mandatory lifting-safety rules.
Installation warnings: (1) Mount vertically with push-rod upward, tilt ≤ 10° - exceeding this causes oil leakage and loss of thrust. (2) Unit is shipped oil-free: fill with DB-25 hydraulic oil before first use. (3) Never weld or tie the push rod - this destroys the fail-safe function.
