The 3UG3051-1AG20: The 102 to 132 V AC supply range at 50/60 Hz means this relay is a direct fit for standard 120 V control transformers common in North American and European panels — no separate DC supply needed. The 1 % relative repeat accuracy means the trip point stays tight across successive starts, so you won't get nuisance trips from a marginal belt slip or load variation. The 10 % relative metering precision is a coarse indication; treat the reading as a trend, not a calibrated tachometer. The 100 mm depth leaves clearance in most shallow enclosures, but verify gland-plate depth if the relay sits behind a door-mounted HMI.
Siemens 3UG3051-1AG20 SIRIUS Monitoring Relay, Underspeed 0.
MPN3UG3051-1AG20
Siemens SIRIUS monitoring relay, 45 mm, underspeed monitoring 0.1–600 1/min, AC 120 V 50/60 Hz, 1 CO contact, screw connection.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026
Specifications
| Parameter | Value |
|---|---|
| Product line / brand name | SIRIUS |
| Parameter | Value |
|---|---|
| Rated value (50 Hz) | 102 ... 132 V |
| Rated value (60 Hz) | 102 ... 132 V |
| Parameter | Value |
|---|---|
| Electrical connection type | screw-type terminals |
| Parameter | Value |
|---|---|
| Mounting type | screw and snap-on mounting |
| Width | 45 mm |
| Height | 100 mm |
| Depth | 100 mm |
Product details
Frequently asked questions
What replaces the 3UG3051-1AG20?
The official replacement is the 3UG4651-1AW30.
What are the key ratings for this relay?
Underspeed monitoring from 0.1 to 600 1/min across four ranges, AC control supply 102 to 132 V at 50/60 Hz, 1 % relative repeat accuracy, 1 CO contact, screw terminals, 45 mm width.
MPN
3UG3051-1AG20