Three-Phase 40A Solid State Relay - KREST40C - Kayama

Technical Description

The Kayama KREST40C Three-Phase Solid State Relay is an electronic component designed for switching loads in three-phase electrical systems using solid-state technology instead of conventional electromechanical contacts.

The KREST40C has a stated rated current of 40 A and is designed for integration into control and automation systems requiring electronic switching of compatible three-phase loads.

Its semiconductor power stage provides electronic switching without mechanical contact movement.

Technical Characteristics

• Brand: Kayama
• Model: KREST40C
• Type: Three-Phase Solid State Relay — SSR
• Number of phases: 3
• Stated rated current: 40 A
• Switching technology: solid state
• Purpose: electronic switching of three-phase loads
• Application: electrical control and automation

Solid-State Technology

Unlike conventional electromechanical contactors and relays, the KREST40C performs switching through semiconductor components.

This eliminates mechanical contact movement during normal switching operation.

System performance depends on proper electrical and thermal sizing.

Three-Phase Configuration

The KREST40C is intended for three-phase applications.

Before installation, verify system voltage, load current, electrical configuration, phase sequence when relevant, load characteristics, protection, control system and thermal conditions.

40 A Rated Current

The stated rated current of the KREST40C is 40 A.

Actual usable current depends on load type, operating current, starting current, surge current, ambient temperature, ventilation, thermal dissipation, switching frequency and duty cycle.

Thermal Dissipation

Solid-state relays generate heat while conducting current.

Proper thermal design is essential for reliable operation.

Heat-sink requirements should be determined according to actual current, ambient temperature, ventilation, duty cycle, switching frequency and panel conditions.

Derating

Under unfavorable thermal conditions, the permissible operating current may need to be reduced.

This derating can be necessary in high ambient temperatures, poorly ventilated enclosures, continuous-duty operation or inadequate thermal dissipation.

Load Characteristics

The type of connected load directly affects SSR sizing.

Three-phase resistive loads, heaters, motors, transformers, inductive loads, capacitive loads and electronic equipment may have significantly different electrical behavior.

Starting Current

Motors, transformers and certain other loads can draw starting currents substantially above their normal operating current.

The relay should therefore not be selected solely according to steady-state load current.

Three-Phase Heating Applications

When properly sized, three-phase SSRs can be integrated into:

• electric ovens;
• heating chambers;
• three-phase heating elements;
• heating machinery;
• automated thermal processes.

Motor Applications

Motor applications require additional consideration because of inrush current and inductive characteristics.

The KREST40C should only be applied to motor switching after confirming that the specific relay characteristics are suitable for the application.

It does not replace motor overload, short-circuit, thermal or machine-safety protection.

Control System Integration

The KREST40C may be integrated with compatible automation systems such as PLCs, temperature controllers, process controllers and industrial control interfaces.

The exact control-signal requirements must be verified before connection.

Electrical Protection

The solid-state relay does not replace circuit protection devices.

Circuit breakers, fuses, surge protection, overload protection and disconnecting devices should be selected according to the electrical design.

Failure Mode and Safety

Semiconductor devices may fail in different modes, including a condition where the output remains conductive.

Critical applications should therefore provide an independent method for disconnecting the load.

The KREST40C should not be used alone as a functional safety device.

Installation

Installation should be performed by technically qualified personnel.

Before energizing, verify system voltage, load current, load type, starting current, control system, protection devices, thermal conditions, heat dissipation, electrical connections and ventilation.

Kayama Quality

The Kayama KREST40C Three-Phase Solid State Relay is part of Kayama's professional range for electronic switching, three-phase electrical control and automation.