Symcom 77C, 77C-LR Catalog Page

2880 North Plaza Drive • Rapid City, SD 57702
[phone] • [phone] • FAX [phone]
www.symcom.com • email:[e-mail]

01/06

Features

Compact design saves
precious panel space.

Model 77Cs are UL listed
overload relays.

Digital programmability
permits precise
customization.

15 parameters can be
programmed for
maximum protection.

Last fault memory
provides instant
troubleshooting diagnostics.

Voltage, current, last 4
faults, kWh usage, and
power factor are recordable
with communications
package.

RS-485 port offers
communication capabilities
with computerized systems
using Modbus.

Protects Single-Phase
Motors from:

• Overload

• Underload

• Jams

• Low voltage

• High voltage

• Rapid cycling

Additional Features:

• Fully programmable

• CSA approved

• CE compliant

• UL and cUL listed

• Automatic or manual reset

• Tamper guard

• RS-485 communication port
(pn RS485MS-2W)

• Remote reset

• Surface and DIN rail
mountable

• Alphanumeric LED
diagnostic display

• Last fault memory

• 5-year warranty

• Made in USA

The Model 77C is a fully-programmable electronic overload relay designed to monitor
single-phase systems. It can be used as a stand-alone product or the communication
port can be used to form a network to monitor the motors from a PC or other control
system. Applications include CONVEYOR SYSTEMS, HVAC EQUIPMENT, PUMPS,

SAWS, GRINDERS, AND OTHER SINGLE-PHASE ELECTRIC MOTORS.

The Model 77C includes a built-in current transformer (CT) which will handle
applications from 2-90 Amps. An external current transformer can be implemented to
handle applications up to 800 Amps. The Model 77C-LR is a low amperage range model
used with motors drawing 1-9 full load amps. The following 14 parameters can be
viewed from the 3-digit alphanumeric display or from a network computer: low voltage
setpoint, high voltage setpoint, CT size/loops setting, overcurrent trip point,
undercurrent trip point, trip class (5, 10, 20, 25, 30, or linear), rapid-cycle timer (RD1),
overload restart delay (RD2), underload restart delay (RD3), number of restarts after an
overload (manual or automatic), RS-485 address, number of restarts after an underload
fault, underload trip delay, and linear overcurrent trip delay. Both the voltage and the line
current can also be viewed while the motor is running.

The Model 77C can be used with an optional RS-485 module (pn RS485MS-2W)
allowing up to 99 Model 77C, Model 777, Model 601,or RM-2000 units to be linked
together using Modbus. From the computer , an operator can control the motor, view the
operating parameters, or log information. SymCom’s Solutions software and RS-485
module are sold separately.

Model 77C

Model 77C-LR

Overload Relay

•

Engineered

Protection

2880 North Plaza Drive • Rapid City, SD 57702
[phone] • [phone] • FAX [phone]
www.symcom.com • email:[e-mail]

01/06

SymCom warrants its microprocessor-based products against defects in material or workmanship for a period of five (5) years from the
date of manufacture.All other products manufactured by SymCom shall be warranted against defects in material and workmanship for
a period of two (2) years from the date of manufacture.For complete information on warranty, liability, terms, returns, and cancellations,
please refer to the SymCom Terms and Conditions of Sale document.

Specifications

•

Operating Points

•

Special Options

Model 77C & 77C-LR

Overload Relay

* If a “J” is displayed in the trip class setting, jam protection is

enabled. If programmed to “Lin”, overcurrent trip delays are
fixed linear-type delays set in OPT1.

**RD2 & RD3 can be programmed to minutes or seconds

in OPT2.

0 Minutes Minutes
1 Minutes Seconds
2 Seconds Minutes

3 Seconds Seconds

OPT2 SETTING RD2 RD3

NOTE: OTHER NECESSARY CONNECTIONS ARE NOT SHOWN

Electrical

Input Voltage 100-240VAC, single-phase
Frequency 50/60 Hz
Motor Full Load Amp Range - 77C 2-25 Amps, single-phase (Loops Required)

26-90 Amps, single-phase (Direct)
91-800 Amps, single-phase (External CTs)

Motor Full Load Amp Range - 77C-LR 1.0-2.5 Amps (Loops Required)

2.0-9.0 Amps (Direct)
Short Circuit 100kA per UL, 10kA per CSA
Power Consumption 10 Watts (max.)
Output Contact Rating SPDT (Form C) Pilot duty rating: 480VA @ 240VAC

General purpose: 10A @ 240VAC

Expected Life

Mechanical

1 x 106 operations

Electrical

1 x 105 operations at rated load

Accuracy at 25° C (77° F)

Voltage ±1%
Current ±3% (Direct, no external CTs)
Timing 5% ± 1 second

Repeatability

Voltage ± 0.5% of nominal voltage
Current ± 1% (Direct, no external CTs)

Safety Marks

UL UL508, UL1053
CE IEC 60947-1, IEC 60947-5-1

Standards Passed

Electrostatic Discharge (ESD) IEC 1000-4-2, Level 3, 6kV contact, 8kV air
Radio Frequency Immunity (RFI), Conducted IEC 1000-4-6, Level 3 10V/m
Radio Frequency Immunity (RFI), Radiated IEC 1000-4-3, Level 3 10V/m
Fast Transient Burst IEC 1000-4-4, Level 3, 3.5 kV input power
Surge

IEC 1000-4-5

Level 3, 2kV line-to-line; Level 4, 4kV line-to-ground

ANSI/IEEE C62.41 Surge and Ring Wave Compliance to a level of 6kV line-to-line
Hi-potential Test Meets UL508 (2 x rated V +1000V for 1 minute)
Vibration IEC 68-2-6, 10-55Hz, 1mm peak-to-peak, 2 hours, 3 axis

Shock IEC 68-2-27, 30g, 3 axis, 11ms duration, half-sine pulse

Mechanical

Dimensions 3.1"H x 5.1 " D x 3.9"W
Terminal Torque 7 in.-lbs.
Enclosure Material Polycarbonate
Weight 1.2 lbs.

Maximum Conductor Size Through 77C 0.65" with insulation

Environmental

Temperature Range Ambient Operating: -40° to 70° C (-40° to 158°F)

Ambient Storage: -40° to 80° C (-40° to 176°F)
Pollution Degree 3
Class of Protection IP20, NEMA 1

Relative Humidity 10-95%, non-condensing per IEC 68-2-3

Programmable Operating Points Range

LV- Low Voltage Threshold 85V - HV Setting
HV- High Voltage Threshold LV Setting - 264V
MULT- # of Conductors or CT Ratio (XXX:5) 77C: 1-10 Conductors or 100-800 Ratio 77C-LR: 1 or 2
OC- Overcurrent Threshold (20-100A) ÷ MULT or 80-120% of CT Primary
UC- Undercurrent Threshold (0, 10-98A) ÷ MULT or 40-100% of CT Primary
TC- Overcurrent Trip Class * 5, J5, 10, J10, 15, J15, 20, J20, 30, J30, or LIn (linear)
RD1- Rapid-Cycle Timer 0, 2 - 500 Seconds
RD2- Restart Delay After Overcurrent 2-500 Minutes/Seconds

(motor cool-down timer)**

RD3- Restart Delay After Undercurrent 2-500 Minutes/Seconds

(dry-well recovery timer)**
#RU- Number of Restarts After Undercurrent 0, 1, 2, 3, 4, A(Automatic)
ADDR- RS485 Address A01-A99
#RO-Number of Restarts After Overcurrent 0, 1, OC1, 2, OC2, 3, OC3, 4, OC4, A(Automatic), OCA

UCTD- Undercurrent Trip Delay 2-60 Seconds

MODEL 77C, 77C-LR SPECIFICATIONS

SymCom recommends using CTs with terminals to
simplify installation.