DWB01 and PWB01 are precise TRMS power factor monitoring relays for 3-phase balanced systems. They can be used for monitoring the actual load of asynchronous motors and other symmetrical loads, where the power factor is almost proportional to the load. The relay measures the power factor (cos ϕ), that is the ratio between the active and the apparent power of a motor. Start/stop input allows to use a manual switch to start and stop the motor, without the need of an auxiliary device. The advantage of using the latch function is that the relay can be kept energized even after the end of the alarm condition. Inhibit function can be used to avoid relay operation when not desired (maintenance, transients). The LED's indicate the state of the relay, alarm, and power supply.
This manual describes the TUEZHONG DWB01 and PWBO01 monitoring relays, which are TRMS load‑guard relays for three‑phase balanced loads. It covers product description, input and output specifications, mechanical and electrical life, and environmental limits.
The document includes wiring diagrams, DIP‑switch settings, mode‑of‑operation explanations, and installation guidance for both DIN‑rail and plug‑in versions, enabling users to configure power‑factor monitoring, start/stop control, and latching or inhibit functions.
| Supply voltage (DIN‑rail version) | 208 to 240 VAC +15% |
|---|---|
| Output relay rating | 8 A SPDT |
| Power ON delay | 1 to 30 s (adjustable) |
| Mechanical life | > 30 × 10⁶ operations |
| Electrical life | > 10⁶ operations at 8 A, 250 V |
| Dielectric voltage | 2 kV AC (RMS) |
| Operating temperature | -20 °C to 60 °C (RH < 95 %) |
| Weight | ≈ 250 g |
| Dimensions (DIN‑rail) | 45 × 80 × 99.5 mm |
| Dimensions (Plug‑in) | 36 × 80 × 94 mm |
The power ON delay is adjustable from 1 to 30 seconds.
The relays use an 8 A SPDT output relay, selectable N.D. or N.E.
The DIN‑rail version accepts 208‑240 VAC + 15 % (and other ranges such as 380‑415 VAC + 15 %).