Safety Brake Rectifier Emits Constant DC Voltage

The Roba-multiswitch, developed for switching safety brakes quickly, is capable of emitting a constantly controlled DC voltage, independent of the mains voltage. This means that complex adaptation of magnetic coils to varying input voltages becomes unnecessary. Overexcitation on switch-on ensures that the connected brakes release extremely quickly.

Two designs are sufficient to cover all mains voltages worldwide, from 100 to 250V AC or 200 to 500V AC, and mains frequencies of 50 to 60Hz. The Roba-multiswitch for the mains voltage range from 200 up to 500V AC is conceived for the operation of safety brakes with 104V DC coils. The constant output voltage is produced using phase segment control. When switched on, the device temporarily (0 to 50ms) emits a bridge voltage, equalling 90 per cent of the applied mains voltage, rectified to the magnetic coil.

After this very short phase, a controlled overexcitation voltage of 180V DC is applied. The overexcitation time - up to the switchover to the operating voltage of 104V DC - can be selected via DIP switch to the levels 0.15s, 0.45s, 1s, 1.5s and 2s. The Roba-multiswitch for mains voltages of 100 to 250V AC works using a controlled overexcitation voltage of 90V DC. The selectable overexcitation times remain the same. The operating voltage (coil nominal voltage) is 52V DC.

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