|Overload-Underload Dual Limit Monitor
A Programmable Digital Load Monitor for machinery monitoring, supervision and control.
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the TG220 Load Monitor.
TG220 measures motor power, kW, RMS voltage, RMS current and Power Factor:
- Max. kW limit — overload alarm
- Min. kW limit — underload alarm
- Dual SPST alarm relays (C1 and C2 is common)
- Start/nuisance trip delay timers
- Optional Hysteresis function on both limits
- Remote Reset and Alarm Blocking
True Digital Design
- no pots, no dials, no screw-drivers.
- 144 samples per cycle at 50 Hz.
- 120 samples per cycle at 60 Hz.
- 4 quadrant digital multiplication.
Ultra Compact DIN Rail Mount
only 1" of rail space.
Current Wire Feeds Through Hole in Unit
Monitor Any Size Motor
(external CT >25Amp.)
peaks up to 75 Amp measured.
High Precision Resolution Measurement
works when amp-meters don’t!
Measures and Displays
kW, kW[%], RMS Voltage, RMS Current and PF(Power Factor)
Peak/Min Capture For All Variables
for accurate limit setting—no guessing.
Limits Programmed in kW[%] or Ture kW
The TG220 is designed for applications where supervision of machine overload, underload or both is required with separate alarms:
- Pumps: Dry-running/cavity protection for centrifugal pumps and control/prevention of over-pressure and by-pass flow for positive displacement pumps.
- Fans and Filters: Supervision of blockage and detection of "not-running" conditions.
- Conveyors and Belts: Jam detection and electronic shear-pin function, plus effective broken belt detection
The drawing shows a typical AC-motor power curve (ex. Pump). The start timer Ts filters out from the regulation the large power surge generated on startup; when Ts expires, limits, hysteresis, Tr etc. becomes active.
When power exceeds the Max. Limit, Tr1 becomes active and when Tr1 expires a max. alarm is generated and relay 1 (C1, NC1) contact is switched open. If power drops back below the Max. Limit before an alarm is generated, Tr1 is cancelled. In this example, hysteresis is used to generate an auto reset once the power returns within the hysteresis band.
A Min. Limit alarm is generated in a similar manner, when power falls below the Min. Limit setting. Tr2 is the reaction timer for the Min. Limit. In case of a min alarm the relay 2 (C2, NC2) contact is switched open.
Note: C1 and C2 is same terminal.