I have visited various facilities who are suffering from the liabilities associated with air over hydraulic braking systems. This includes excessive maintenance due to the numerous moving parts associated with these packages, as well as the oil involved which can get quite messy (and freeze in the winter time). Indeed, the hydraulic brake systems have served their purpose and successfully helped overhead cranes function for several years. However, innovation and change is inevitable and we have now found a far superior braking system which supersedes its air over hydraulic predecessor.
Enter the AC Thruster Braking package which is used in conjunction with a foot pedal and Controller which consists of a variable frequency drive that allows for constant torque, allowing the end user to set accel/decel times (and numerous other fun and useful programs). What makes it especially convenient is that these AC Thruster Drum brakes can be manufactured as “drop-in” replacements for the older brakes in various non-AISE dimensions including 14” and 18” (so neither real estate nor purchasing new brake wheels become an issue).
The benefits of using these newer packages far exceed their costs. Permanently excluded are control cylinders, valves, pressure switches, hydraulic tubing, etc. If used/installed properly, the AC Thruster Braking system (which works in both AC and DC applications), will require very little maintenance. The brakes can now become holding brakes due to the VFD component of the system, and thus there is less wear and ultimately a much slower rate of depreciation. The thruster can function under very high temperatures, especially if you use a special type of fluid which can withstand higher temperatures. The price of a new braking system is not inexpensive, but the total cost of ownership is far less than its air over hydraulic counterpart.
Nothing beats the feeling of seeing a satisfied crane operator, and having a smooth, reliable, and low-maintenance braking system will invariably yield a sense of satisfaction for most anybody working with overhead cranes.