Prospeed Closed Loop Control system for Eddy Current Brakes COMMANDER has developed an advanced and highly efficient Closed Loop Control System called Prospeed. For the effective control of Eddy Current Brakes, Prospeed is used on high integrity overhead travelling cranes and other equipment where accurate and constant speed control and load safety are paramount. When used in conjunction with the ComDrive Eddy Current Brake Unit, slip-ring wound rotor induction motor, contactor switch gear and specially graded resistance units, the Prospeed Closed Loop Control System provides a reliable failsafe speed control solution for both Crane and Hoist applications. The Prospeed Closed Loop Control System can also be used to replace most other makes of open/closed loop control for eddy current brake systems. The all-steel design chassis plate can be easily adapted for alternative mounting footprints. The Prospeed Closed Loop Control System is fully self contained and fitted with all necessary controls and instrumentation to set up the required speeds, without the need to use external instruments. Accurate pre-set speed control up to 5 speeds can be achieved in both directions of movement between 7.5% and 60% of the applied motor rated speed. LED indication is provided to indicate which speed step is active (selected). A custom designed and manufactured Emergency Stop safety relay is incorporated to monitor for current and voltage failures. This safety relay is often connected into the external protective control system (Main Line Contactor and/or No-volt relay circuit). All components used have been sized for at least 2.5 x safety factor, both on voltage and current thus enabling high reliability to be in-built as standard. The Prospeed Closed Loop Control System can be supplied as an integral part of a control scheme or can be housed inside a separate control cubicle. The Prospeed Closed Loop Control System provides a varying D.C. Voltage and Current to the ComDrive field winding to produce a magnetic field between the stator and solid moving rotor. The slip ring rotor voltage from the motion drive motor is used to represent motor speed, this is monitored by the Prospeed Closed Loop Control System to vary the applied magnetic field strength in order to achieve the required pre-set speed. Separate contactor control of rotor resistance switching assists the motor speed torque development. The Prospeed Closed Loop Control System uses the motor slip ring voltage as a speed reference, which is compared to a pre-set locked rotor reference voltage. The resulting differential voltage is then applied to an OP amp firing circuit, which in turn varies the output voltage and current of a single-phase Thyristor stack to control the ComDrive field coil effect. The system employs hard wired logic to ensure a high degree of integrity. The Motor rotor slip-ring voltage is used to accurately monitor the drive motion motor up to 60% of its nominal speed. The maximum output voltage is 360V D.C., the maximum current is 10 Amps. Ambient temperature range is -5ºC to +55ºC. Features: Ammeter & Voltmeter for system set up. Highbright LED indicators for each active speed Dual channel safety relay with continuous monitoring of:- - Prospeed Closed Loop Control System Hardware - ComDrive inter-connecting cabling - ComDrive field coils - Voltage to ComDrive Unit - Current to ComDrive Unit Locking, recordable multi-turn pre-set speed potentiometers Fully compliant with EU (EEC) EMC & RFI standards Type Tested for Duty Cycle, Seismic & Environmental Off Position braking to assist operational brakes ComDrive field current build up prior to the operation brakes being released, operating brake(s) release to prevent hook initially lowering before raising when operating brake(s) released. Typical Applications: Nuclear Fuel Reprocessing Handling Operations Nuclear Reactor Refuelling (Charge) Cranes Power Station Turbine Hall Cranes Heavy Lift Shipbuilding Cranes Other Electrically Power Machinery or Plant Vessel Slip-way Winches