CHINT JR-36-20 Thermal Overload Relay

Suitable for overload and phase failure protection of industrial motors; a classic supporting component for motor control.

Basic Application & Standards

Application: AC 50/60Hz, rated voltage up to 690V, for continuous/intermittent three-phase asynchronous motors, providing overload + differential phase failure protection.

Not suitable for standalone short-circuit protection; must be used with fuses/circuit breakers.

Complies with GB/T 14048.4/5 and IEC 60947-4-1.

Can form a QC36 electromagnetic starter with CJT1 contactors.

Ambient conditions: -5℃ ~ +40℃ (24h average ≤ 35℃), altitude ≤ 2000m, inclination ≤ 5°, no explosive or highly corrosive media.

Key Technical Parameters
Frame current: 20A

Setting current available in multiple ranges (0.25–0.35A, 3.2–5A, 10–16A, 14–22A, etc., selected as required).

Trip class: Class 10A

Auxiliary contacts: 1 NO + 1 NC

AC-15 380V: 0.47A; DC-15 220V: 0.15A

Wiring specifications:

Main circuit: 1.0–6 mm² (M5 screw)

Auxiliary circuit: 0.5–1 mm² (M3 screw)

Protection characteristics

1.05 × setting current: cold state, no operation within 2h

1.2 × setting current: hot state, operates within 2h

1.5 × setting current: operates within 2 minutes after thermal equilibrium

7.2 × setting current: cold state, operates at 2s < t ≤10s

Fast differential operation under phase failure

Functions: temperature compensation, manual/auto reset selectable, test button (manual trip simulation)
Structure & Installation

Three-phase bimetallic structure; independent mounting (not DIN‑rail clip type; screw fixing required)

Front panel: setting current adjustment knob, reset button, reset mode switch

Main circuit: three-phase input/output; auxiliary contacts for control circuit

Selection, Replacement & Usage Notes
Setting current must match motor rated current (prefer a range that covers the rated value).
Replacement:

Different current ratings of JR36-20 share interchangeable bases.

Cross-brand equivalents: Delixi JR36-20, People Electrical JR36-20.

Upgrades: CHINT JR-36-20 Thermal Overload Relay.

Do not operate with wet hands.

Maintain distance ≥50mm from heating components.

Inspect bimetal for deformation after short circuit.

Control circuit must include short-circuit protection.

Typical Setting Current Sub-Models

Sub‑Model	Setting Current Range	Suitable Motor Power (380V 3‑phase)
JR36-20/10–16	10–16A	5.5–7.5kW
JR36-20/14–22	14–22A	7.5–11kW

CHINT JR36-20 Thermal Overload Relay

Core Description: Bimetallic thermal overload relay for overload and differential phase failure protection of three-phase asynchronous motors.

Frame current: 20A, trip class: Class 10A.

Not for standalone short-circuit protection; must be used with fuses/circuit breakers.

Basic Specifications & Standards

Item	Details
Applicable circuit	AC 50/60Hz, rated voltage up to 690V, three-phase system
Protected object	Continuous/intermittent three-phase asynchronous motors, against burnout from overload/phase loss
Standards	GB/T 14048.4/5, IEC 60947-4-1
Ambient temperature	-5℃ ~ +40℃ (24h average ≤ 35℃)
Altitude	≤ 2000m
Installation inclination	≤ 5°
Structure	Three-phase bimetallic type, independent mounting (screw fixed)

Key Technical Parameters

2.1 Setting Current & Full Series Sub-Models

Sub‑Model	Setting Current Range	Suitable Motor Power (380V)
JR36-20/0.25-0.35	0.25~0.35A	0.12~0.18kW
JR36-20/0.32-0.5	0.32~0.5A	0.18~0.25kW
JR36-20/0.45-0.75	0.45~0.75A	0.25~0.37kW
JR36-20/0.63-1	0.63~1A	0.37~0.55kW
JR36-20/0.8-1.25	0.8~1.25A	0.55~0.75kW
JR36-20/1-1.6	1~1.6A	0.75~1.1kW
JR36-20/1.25-2	1.25~2A	1.1~1.5kW
JR36-20/1.6-2.5	1.6~2.5A	1.5~2.2kW
JR36-20/2-3.2	2~3.2A	2.2~3kW
JR36-20/2.5-4	2.5~4A	3~4kW
JR36-20/3.2-5	3.2~5A	4~5.5kW
JR36-20/4-6.3	4~6.3A	5.5~7.5kW
JR36-20/5-8	5~8A	7.5~11kW
JR36-20/6.3-10	6.3~10A	11~15kW
JR36-20/8-12.5	8~12.5A	15~18.5kW
JR36-20/10-16	10~16A	18.5~22kW
JR36-20/12.5-20	12.5~20A	22~30kW
JR36-20/14-22	14~22A	30~37kW

2.2 Electrical Performance

Trip class: Class 10A (at 7.2× setting current, cold state: 2s < t ≤10s)

Auxiliary contacts: 1 NO + 1 NC, electrically isolated

Wiring: Main 1.0–6 mm² (M5); Aux 0.5–1 mm² (M3)

Terminal marking:

Main: L1/L2/L3 (line), T1/T2/T3 (load)

Control: 95‑96 (NC), 97‑98 (NO)

2.3 Protection Characteristic Curve

Multiple	Condition	Trip Time
1.05×	Cold	No operation within 2h
1.2×	Hot	Operates within 2h
1.5×	Thermal equilibrium	Operates within 2 min
7.2×	Cold	2s < t ≤10s
Phase failure	Any	Fast differential operation

Structural Features & Functions
Three-phase bimetal with differential design for fast phase‑loss protection
Continuous setting adjustment via front knob
Manual / automatic reset (side switch)
Test button (red) for simulating overload trip
Temperature compensation reduces ambient influence
Mechanical trip indicator for fault diagnosis
Installation & Wiring

4.1 Installation Rules

Independent mounting with M4/M5 screws

Inclination ≤ 5° from vertical

Keep ≥50mm from contactors, transformers and other heat sources

Well ventilated, free from heavy vibration, dust, corrosive gas

4.2 Standard Wiring

Main circuit: Contactor output → L1/L2/L3 → T1/T2/T3 → Motor stator
Control circuit: NC (95‑96) in series with contactor coil
NO (97‑98): For fault alarm, indicator light or PLC input
Cross‑Brand Replacement & Upgrade

5.1 Direct Replacements

Brand	Replacement Model	Compatibility
Delixi	JR36-20 series	Identical size & parameters
People Electrical	JR36-20 series	Same mounting holes
Changshu Switch	JR36-20 series	Compatible terminals

5.2 Recommended Upgrades

Original	Upgrade	Advantage
JR36-20	CHINT NR2-25	DIN‑rail mount, more accurate
JR36-20	CHINT NXR-25	Electronic type, full protection

Troubleshooting

Symptom	Possible Cause	Solution
No trip on overload	Setting too high; element damaged; bimetal deformed	Reset to motor rated current; replace unit
Unnecessary tripping	Setting too low; high ambient temp; poor ventilation	Adjust setting; improve cooling
No phase‑loss protection	Wrong wiring; differential mechanism fault	Check wiring; replace relay
Hard to reset	Mechanism jam; not cooled	Wait 5–10 min; retry gently
Auxiliary contact failure	Oxidation; loose wiring	Clean contacts; retighten