S24 Modular contactor
S24 modular contactors: S24 switching and control of electrical loads in modular boards.
- Series: S24 range for modular DIN-board assemblies.
- Function: switching of loads from control signals.
- Integration: designed to work with protection and automation devices.
- Use: lighting, services, HVAC and scheduled loads.
S24 modular contactors: switching with a 230 V AC coil
Solera S24 modular contactors connect and disconnect loads in response to a signal applied to the coil. The published range comprises six references: two-pole versions with 2NO contacts and four-pole versions with 4NO contacts, with nominal currents of 25, 40 and 63 A. NO means normally open: the power contacts close when the coil is energized. These are switching devices; selection must consider both the load circuit and the control circuit.
Differences between the six S24 references
| Reference | Poles | Contacts | Nominal current | 18 mm modules |
|---|---|---|---|---|
| S24CM2A25 | 2P | 2NO | 25 A | 1 |
| S24CM2A40 | 2P | 2NO | 40 A | 2 |
| S24CM2A63 | 2P | 2NO | 63 A | 2 |
| S24CM4A25 | 4P | 4NO | 25 A | 3 |
| S24CM4A40 | 4P | 4NO | 40 A | 3 |
| S24CM4A63 | 4P | 4NO | 63 A | 3 |
Applications and selection criteria
They provide centralized or scheduled control of lighting, building services and HVAC loads where load characteristics suit the device’s switching capacity. For example, a time switch can command the coil while the contactor switches the load. This requires checking the programmer output, coil voltage and coil consumption; a shared DIN format does not establish automatic compatibility.
Select the required poles and contacts according to the circuit diagram. Then check the operating current and utilization category applicable to the load, its starting current and switching frequency. Nominal values of 25, 40 or 63 A must not be applied without verification to motors, compressors or LED assemblies. The data sheets declare 2NO or 4NO contacts; do not assume NC or auxiliary contacts are included.
Mounting is on a 35 mm DIN rail. S24CM2A25 occupies one module; the two-pole 40 and 63 A versions occupy two; all four-pole versions occupy three. The data sheets specify an ambient operating temperature of −5 to +40 °C. Allow the space and panel mounting conditions required by the documentation, and coordinate circuit protection separately.
Frequently asked questions
Does a 230 V AC coil mean the load must operate at the same voltage?
Coil voltage refers to the control circuit; contact voltage and capacity refer to the switched circuit. These are separate characteristics. The declared coil voltage for these six references is 230 V AC: check the power circuit and product markings separately. Do not infer suitability for 24 V or DC control.
Can a 63 A contactor switch any motor or LED load drawing less than 63 A?
That figure alone is insufficient. Selection depends on utilization category, voltage, load type, starting current and switching frequency. Check the declared capacity for the specific application; nominal current alone does not establish an allowable motor power or number of LED luminaires.
Does the contactor replace an MCB, residual current device or motor protection circuit breaker?
No. The contactor switches in response to the control signal. Overload, short-circuit and residual current protection must be provided by suitable devices coordinated for each circuit. For a motor, also check the specific motor protection and its coordination with the contactor.