JVR(800-1)is Multi-function monitoring and protection device which includes timing, counting and voltage show, over-voltage and under-voltage protection, open-phase protection and phase sequence protection. It uses advanced microprocessor chip and nonvolatile storage technology. Chinese LCD is easy to operate. Show the current supply voltage, cut off power to protect the equipment when meet over-voltage, under-voltage, phase loss and phase reversal faults. It is fit for various of passenger elevator, goods lift, hoist, machine tool and other devices which frequent start.