OMRON G3PA-240B-VD Solid State Relay

IL Omron G3PA series single-phase solid state relay (RSS) with integrated heat sink, zero-crossing turn-on, Montaggio su guida DIN, directly driven by PLC DC signals. Widely used for non-contact switching control of heating elements, fans and lamp loads.

Nota importante: Questo modello è fuori produzione. Only stock units are available or alternative models should be selected.

1. Definizione del codice modello

G3PA: Nome della serie, solid state relay with integrated heat sink

2: Monofase, AC24~240V output specification

40: Rated load current 40A

B: Built-in heat sink

VD: DC5~24V DC input control, opto-triac isolation, zero-crossing turn-on

2. Specifiche elettriche principali

✅ Input Side (Control Terminals +A1, -A2)

Tensione di controllo: DC5~24V, operating range DC4~30V

Maximum input current: 7mA (directly drivable by PLC output point)

Operating voltage ≤DC4V; Reset voltage ≥DC1V

Isolamento: Opto-triac isolation

✅ Output Side (Load Terminals 1, 2)

Rated load voltage: AC24~240V, operating range AC19~264V (50/60Hz)

Rated load current: 40A @40℃; derate to 36A for dense side-by-side mounting

Surge withstand current: 440UN (60Hz, 1 ciclo)

I²t: 1260 A²s

On-state voltage drop: ≤1.6V RMS

Switching characteristic: Zero-cross turn-on, reduces switching surge

Operare / release time: Within half cycle of load power supply +1ms

✅ Environmental & Meccanico

Temperatura operativa: -30℃ ~ +80 ℃ (nessuna condensa)

Montaggio: DIN rail or screw mounting; screw type terminals

Dimensioni: W47 × H100 × D100 mm

Dielectric strength between input and output: AC4000V

3. Scenari applicativi tipici

Controllo della temperatura: Heating tubes, ceramic heaters, infrared heating (più comune)

Illuminazione: High power lamp banks, halogen lamps

Motori: Small single-phase fans (resistivo / weakly inductive load preferred)

Nota: Inductive loads and loads with large starting inrush current require additional varistor and RC snubber protection.

4. Linee guida per il cablaggio
5. +A1, -A2: DC control signal, good polarity tolerance. It is recommended to connect PLC positive output to A1.
6. Terminali 1, 2: Connected in series to AC load circuit, L/N non-polarity.
7. Circuito soppressore RC + varistor connected in parallel at output terminals for inductive loads.
8. Derate current and reserve heat dissipation clearance when multiple SSRs are installed side by side on DIN rail.
9. Replacement Models for Discontinued Product
10. Upward replacement within same series: G3PA-260B-VD (60UN, DC5~24V input). Same pin layout with higher capacity.
11. New generation alternative: G3PE series G3PE-245B, 45A DC control, Montaggio su guida DIN, sostituzione diretta.
12. Domestic compatible SSR: 40A solid state relay, DC5-24V input, AC240V, zero-cross type with integrated heat sink.
13. Risoluzione dei problemi comuni
14. Input LED does not light: Check PLC output voltage and broken wiring; insufficient input current to drive SSR.
15. LED lights but load does not turn on: Loose output terminals, broken load; internal triac damage.
16. Load remains energized after control signal removed: SSR short-circuit failure (common for heating loads), usually caused by overheating or surge breakdown.
17. Frequent false triggering: Control cable runs in parallel with power cable causing interference; connect 1000pF anti-interference capacitor at input side.
18. Note sulla selezione
19. Carichi resistivi: Derate to 0.7 times rated current for selection.
20. Heating loads have low cold resistance with large starting inrush current, sufficient current margin is required.
21. Further derate when ambient temperature >40℃ or densely mounted.
22. Solid state relay has no mechanical contacts, cannot serve as safety disconnect switch. Circuit breaker must be fitted on main circuit.

OMRON G3PA-240B-VD (40A DC to AC Zero-cross SSR) Casi applicativi tipici

Product Recap: Integrated heat sink, Montaggio su guida DIN, DC5~24V input, AC24~240V 40A, zero-cross turn-on. Directly driven by PLC, mainly suitable for resistive loads. RC+MOV snubber required for inductive loads.

Caso 1: Temperature Control System – Industrial Heating Tube Control (Il più popolare)

Applicazione

Forni, hot presses, plastic dryers, mold temperature machines, food baking lines, single-phase 220V heating tubes, max power ~8kW (220V×40A), PID power regulation by PLC + regolatore di temperatura.

Configurazione del sistema

1. Controllare: Transistor output DC24V from temperature controller / PLC connected to A1/A2 of G3PA; zero-cross switching reduces grid harmonic distortion.
2. Circuito principale: AC220L → SSR terminal 1; terminale 2 → heating tube → N.
3. Protezione: 3P circuit breaker + fast fuse at upstream; thermocouple over-temperature protection is recommended for heating tubes.
4. Snubber: RC optional for resistive loads; 470V varistor is recommended for high power applications to absorb grid surge.

Derating Recommendation

Continuous long-term operation: Load current controlled within 28A (0.7×rating); reduce to 24A for side-by-side multi-unit installation.

Vantaggi

Contactless operation, no contact erosion even under frequent switching (several times per second), higher PID temperature control accuracy.

Common Pitfall

Heating tubes have large cold-state inrush current. Continuous full-current operation tends to break down SSR; do not treat rated 40A as continuous operating current.

Caso 2: High Power Halogen / Infrared Lamp Bank Control

Applicazione

UV curing lamps, infrared heating lamps, industrial inspection light sources, infrared radiation panels for drying lines, 220V AC lamp banks.

Configurazione del sistema

PLC DC24V output drives SSR; lamp load connected in parallel to SSR output terminals.

Halogen lamp has extremely low cold resistance, inrush current at switch-on can reach 8~10 times rated current.

Precauzioni

1. Zero-cross G3PA is well suited for lamp loads, turn-on at voltage zero point to reduce inrush.
2. Heavy derating is mandatory: lamp load at 0.4~0.5 times SSR rating; load ≤20A for this 40A SSR.
3. NTC surge limiting thermistor in series is recommended.

Vantaggi

Silent switching, no electric arc under frequent on/off, suitable for automated production line light sources.

Caso 3: Tifosi / Small Single-phase Motors (Carico induttivo)

Applicazione

Air duct heating matched fans, cabinet high-power cooling fans, small conveying single-phase fans for continuous start-stop control.

This is inductive load, RC snubber + MOV varistor must be installed (100Ω/2W +0.1μF/400VAC +470V varistor).

Sistema

PLC controls SSR to start/stop fan; circuit breaker fitted upstream of SSR.

Limitazione

Not suitable for frequent forward/reverse rotation of motor; not applicable for high-power motors with huge starting surge.

Back EMF generated at motor power-off can easily damage SSR, RC snubber is essential.

Caso 4: Solenoid Valve Bank, AC Contactor Coil Drive (Small Inductive Load)

Applicazione

Attrezzature per l'imballaggio, pneumatic production lines, multiple parallel AC220V solenoid coils controlled centrally by PLC.

Configurazione del sistema

SSR output drives multiple parallel AC220V solenoid coils; RC+MOV connected in parallel to SSR terminals.

Note

Solenoid coil is inductance, generates high voltage spike at turn-off; total load current cannot exceed 40A.

Minor chattering of solenoid after SSR turn-off may occur due to RC leakage current. Soluzione: connect 10kΩ/5W bleeder resistor across load terminals.

Caso 5: 220V AC Motorized Rollers for Conveyor Lines / Small Conveying Equipment

Applicazione

Logistics sorting lines, packaging conveyor lines, start-stop control of single-phase 220V motorized rollers.

Punti chiave

RC+MOV snubber mandatory for motor inductive load; not suitable for frequent jogging with heavy impact, applicable for long run operation with long interval start-stop.

Caso 6: Environmental Test Chamber Heating Circuit

Applicazione

Constant temperature & humidity chamber, aging test chamber, resistive heating circuit with continuous PID power regulation.

Configurazione del sistema

PID DC24V output from temperature controller drives G3PA; multi-section heating zone control with multiple G3PA mounted side by side on DIN rail.

Note chiave

Derate current and reserve heat dissipation clearance for side-by-side installation; ambient temperature around SSR must not exceed 60℃.

Load Selection Summary Table

General Usage Prohibitions for G3PA-240B-VD

1. ❌ Not for large air compressors, high-power single-phase motors (excessive starting surge)
2. ❌ Cannot act as safety disconnect switch, independent circuit breaker required for main circuit
3. ❌ Not suitable for high-frequency high-voltage inductive loads; triac short-circuit failure risk (SSR stuck ON, load continuously powered, risk of over-temperature fire in temperature control systems)
4. ❌ Further current derating required when ambient temperature＞60℃

G3PA-240B-VD Fault List by Application Scenario

Modello: Omron G3PA-240B-VD, 40A DC input zero-cross SSR; main failure modes: permanent short-circuit at output (most hazardous), failure to turn on, intermittent false triggering.

Precaution: If SSR fails shorted, load stays energized continuously. Over-temperature fire risk is high for heating systems. Independent over-temperature protection must be fitted on main circuit.

Caso 1: Heating Tube / Forno, Mold Temperature Machine (Carico resistivo, Più comune)

Fault1: SSR short-circuits after operating for a period, heating never stops

Sintomo: PLC control signal removed, no input at A1/A2, heating tube remains heated; SSR housing very hot.

Causa ultima:

1) Long-time full current operation without 0.7 declassamento; insufficient heat dissipation with side-by-side mounting.

2) Aging heating tube with partial short circuit, surge current breaks triac.

3) Grid voltage spike without varistor protection.

Rimedio: Control load current ≤28A; install 470V varistor; periodically test insulation of heating tube; add independent over-temperature thermostat for hard cut-off.

Fault2: Large temperature fluctuation under PID control, intermittent heating

Sintomo: Temperature controller output normal, heating cuts in and out randomly.

Causa ultima:

1) Insufficient output current from PLC, voltage drop on cable.

2) Loose SSR terminals, contact resistance generates heat.

3) Oxidized wiring of heating tube, scarso contatto.

Rimedio: Stringere i terminali (torque 0.8~1.0N·m); check driving capacity of PLC transistor output; replace aged heating tube.

Colpa3: SSR indicator LED on, but no heating

Causa ultima: Broken output circuit, burnt heating tube; open-circuit damage of internal triac.

Rimedio: Measure resistance of heating tube after power-off; measure AC voltage across SSR output terminals.

Caso 2: Halogen / Infrared Lamp Bank

Fault1: SSR damaged immediately upon lamp switch-on

Sintomo: SSR burns out right after lamp activation even if average current is low.

Causa ultima: Extremely low cold resistance of halogen lamp, inrush current reaches 8~10 times rated; zero-cross turn-on still cannot eliminate huge surge without derating.

Rimedio: Limit load current to 0.4~0.5×SSR rating; fit NTC surge suppression thermistor in lamp circuit; prefer lamp-specific SSR.

Fault2: Lamp flickering

Causa ultima: Fluctuating supply voltage; lamp aging; internal component aging of SSR.

Rimedio: Replace aged lamps; verify power supply stability.

Caso 3: Single-phase Fan, Small Motor (Carico induttivo)

Fault1: SSR breaks down every time fan stops

Sintomo: Fan runs normally, SSR fails when control signal turns off.

Causa ultima: Inductance of motor winding generates high back EMF at power-off; RC+MOV not fitted.

Rimedio: Install RC snubber (100Ω/2W +0.1μF/400VAC in series) +470V varistor, wire directly close to SSR terminals.

Fault2: Fan slowly rotates after SSR turned off

Sintomo: Fan does not fully stop after PLC signal removed, low speed rotation.

Causa ultima: Leakage current introduced by RC snubber, weak voltage induced on motor winding.

Rimedio: Fit 10kΩ/5W bleeder resistor across motor terminals; or use mechanical contactor for complete cut-off.

Caso 4: AC220V Solenoid Coil Bank (Carico induttivo)

Fault1: Solenoid randomly pulls in (falso innesco)

Sintomo: Solenoid occasionally chattering or actuating without PLC output signal.

Causa ultima: RC leakage current; electromagnetic interference when control cable runs parallel with power cable; excessively long control wire.

Rimedio: Fit 10kΩ/5W bleeder resistor across load terminals; separate routing for control and power cables; fit 1000pF anti-interference capacitor at input side.

Fault2: SSR damaged after multiple switching cycles

Causa ultima: High voltage spike from coil turn-off without RC+MOV protection.

Rimedio: Install RC+MOV; do not connect excessive solenoids in parallel, derate total current to 0.6×rating.

Caso 5: Conveyor Motorized Roller

Fault1: Unstable start-stop of roller, occasional start failure

Sintomo: Roller sometimes fails to start even when control signal is sent to SSR.

Causa ultima: Large motor starting surge; insufficient SSR margin; voltage drop on cable.

Rimedio: Reduce load capacity; verify power cable gauge; RC+MOV mandatory for inductive load.

Fault2: Severe overheating of SSR

Causa ultima: Long-time heavy current operation; poor heat dissipation for multiple SSR mounted side by side on DIN rail.

Rimedio: Increase mounting gap between SSR units; reduce load current; add auxiliary cooling fan if necessary.

General Common Faults (Applicable to All Scenarios)

1. Input indicator LED at A1/A2 does not light

Troubleshooting sequence:

1) Check PLC output, confirm DC24V present.

2) Broken control wire, polarità invertita (tolerated to some extent, long-term reverse polarity damages input LED).

3) Burnt input circuit of SSR.

2. Input LED normal, no output action

Risoluzione dei problemi: Main power supply available; loose output terminals; open-circuit damage of internal triac.

3. Random SSR failure under high ambient temperature

Causa ultima: Ambient temperature＞60℃, heat dissipation deteriorates, device characteristic drift.

Rimedio: Migliorare la ventilazione dell'armadio; further derate current; mount SSR away from heat-generating components.

4. Random SSR false actuation caused by interference

Sintomo: SSR turns on/off irregularly during equipment operation.

Contromisure:

1) Separate cable trunking for control signal and power cable, avoid long parallel routing.

2) Fit isolation relay at PLC output side.

3) Connect 1000pF high voltage ceramic capacitor at input side.

Rapid Fault Diagnosis Procedure (For On-site Commissioning)

1. Disconnect AC main power, keep DC24V control power on, check whether SSR input LED follows PLC signal.
2. Spegnimento, measure resistance across SSR output terminals:

Normal state (no input signal): High resistance, Mega-ohm level.

Resistance close to conducting state without input: SSR short-circuited, DO NOT energize!

3. Power on with load, measure AC voltage across SSR output terminals:

With ON signal: Voltage drop across SSR ≤1.6V.

With OFF signal: Voltage across SSR close to AC220V.

4. Check SSR housing temperature; improve derating or heat dissipation if temperature exceeds 70℃.

Norme di sicurezza

1. Short-circuit failure is the typical failure mode of this SSR. Independent mechanical over-temperature protection must be fitted for heating applications; do not rely only on PLC and SSR.
2. Do not run long-term test without RC+MOV for any inductive load.
3. SSR shall not be used as safety isolation switch; main circuit breaker must be opened for equipment maintenance.