RR3 Series Rail Mount 230VAC 1CO 10A Single Phase Analog Voltage Protection Electronic Relay
The RR3VP01 protects single-phase equipment from voltage excursions outside a safe band, tripping a relay output if the supply drops too low or spikes too high. Adjustable low and high setpoints plus a configurable time delay mean you can tune it to your equipment's actual tolerance rather than accepting a fixed factory threshold.
A simple to install voltage protection relay for single phase supplies:
- Easy adjustment of setpoints by potentiometer
- Time delay 0-20 seconds
- Status LEDs for easy diagnosis
Technical Details
Frequently Asked Questions
What does the time delay setting do?
It delays tripping by 0-20 seconds after detecting an out-of-range voltage, letting the relay ride through brief transients or dips rather than tripping on every momentary fluctuation.
What does hysteresis mean here?
The 5V hysteresis band prevents the relay chattering on and off when voltage sits right at a setpoint threshold, requiring voltage to move a further 5V before switching back.
Is this for single-phase or three-phase supplies?
Single-phase only — check EMAS's RR3VP02 if you need three-phase voltage protection.
How do the status LEDs help with diagnosis?
They show at a glance whether the relay is within range, tripped low, or tripped high, speeding up fault-finding without needing a meter.
Industry Applications
- Motor & equipment protection — preventing damage from under/over-voltage conditions
- Generator & backup power systems — detecting out-of-tolerance supply before it reaches sensitive equipment
- Panel builders & OEMs — adding voltage supervision to single-phase control circuits


