Toshiba Model RC803 Overcurrent/Undercurrent Electronic Relay

Toshiba Updated: 2007-07-18
Toshiba Model RC803 Overcurrent/Undercurrent Electronic Relay

The RC803A Current Relay is designed to control and protect processes and equipment by monitoring the current of an induction mortor or other similar loads.


• Conveyers: Protect against jams and excessive loads. Indicates broken or loose belts.
• Pumps: Protect against dry running, clogging, and worn bearings.
• Fans: Monitor fans for worn or broken belts. Indicates closed dampers or blocked belts.
• Chippers & Saws: Indicate dull or damaged cutting blades and teeth. Features
• Overcurrrent and undercurrent adjustable trip points.
• Adjustable start-up delay.
• Fail safe construction-relay operates as soon as the input current exceeds the preset level or power supply is de-energized.
• Individual SPDT (1NO/NC) output contact for overcurrent and undercurrent trip.
• Separate LED indication for overcurrent and undercurrent trip
• Small and compact size

RC803A - Overcurrent /Undercurrent
Type of current sensing  Overcurrent/Undercurrent
Rated current Adjustable range  5A Max . Continuous 0.5-5A
Accuracy  10%
Reset hysteresis  10%
Temperature error (±30?C)  ± 5%
Supply voltage  100 ~ 120V AC 200 ~ 240V AC
Frequency (± 10%)  50/60Hz
Start up delay, adjustable  0 (inst.)-30 sec.
Response delay, adjustable  0 (inst.)-3 sec.
Ambient temperature  -10-+50?C
Power consumption  3.5VA
Current transformer burden  0.1VA
Output contact arrangement  Overcurrent; SPDT (1 NO-NC)
Undercurrent; SPDT (1 NO-NC)
Output contact rating*  Volt.  Continuous Current  Breaking Current
120V AC  5A  5A (Inductive, pf =0.4)
240V AC  5A  3A (Inductive, pf=0.4)
24V DC 5A 0.3A (L/R =15 ms)
120V DC 5A 0.15A (L/R = 15 ms)
240V DC  5A  0.1 A (L/R = 15 ms)
Dielectric withstand voltage between terminals and ground  2000V AC-1 min.
Weight  0.75kg (1 .7 lbs.)