Product Description

9905-992 is a ProTech de-energize-to-trip model. This overspeed protection device is one of the models with two input voltages. Speed-sensing units A and B each has a 24 Vdc power supply, while the power supply for unit C is 120 Vac/dc. Aside from that, the three units are identical.

One key feature of model 9905-992 is the operator interfaces. There are three of these on the front panel, one for each speed-sensing unit. The LCD and keypad on the interface are used to program the system and set parameters such as MPU Fail Set Point and Trip Speed Set Point. Access to PROGRAM mode is restricted by the location of the key switch to switch between modes. This key switch is located inside the key-locked enclosure.

The LCDs also display a number of parameters while the ProTech 9905-992 system is in MONITOR mode. This includes:

• Present Speed (the default first parameter displayed)
• Peak Speed
• Trip Cause (if applicable)
• Trip on MPU Failure Option
• MPU Gear Teeth
• MPU Failed Set Point
• MPU Failed Timeout
• Trip Speed Set Point

When functions fail to operate normally, an error code is displayed. Some issues, such as a tripped unit or a failed MPU, will also trigger an LED functional status indicator to illuminate. In the event of a tripped unit, an alarm output will sound as well.