Molybdenum disilicide, commonly known as MoSi₂, is a specialist heating-element material used in extremely high-temperature furnaces and kilns.
Unlike normal-resistance elements, MoSi₂ elements have a much lower electrical resistance when cold. Their resistance rises rapidly as they heat, creating a potentially high start-up current that must be carefully controlled.
MoSi₂ elements are commonly found in:
They are typically selected where process temperatures exceed the practical limits of conventional metallic heating elements.
MoSi₂ elements offer:
At high temperatures, the element forms a protective silica layer that helps resist further oxidation.
When cold, an MoSi₂ element can draw considerably more current than it does at normal operating temperature.
Applying full voltage during start-up may cause:
The controller must limit the current and increase the applied voltage progressively as the element warms.
Phase-angle firing with current limiting and soft start is normally the preferred solution.
Phase-angle control adjusts the RMS voltage during every mains cycle, allowing the element to warm gradually without excessive current.
Once the element reaches operating temperature, the controller continues to regulate the power required by the process.
Key benefits include:
Current limiting must be configured using the element manufacturer’s electrical data.
REVO C provides the advanced control functions required for MoSi₂ heating applications.
Available functions include:
REVO C can control directly connected elements or transformer-fed systems, depending on the element voltage and furnace design.
An MoSi₂ power controller cannot be selected from heater kW alone.
To specify the correct solution, we need:
CD Automation can help you select the correct controller, current limit, firing mode and transformer arrangement for safe and reliable operation.
Speak to a Power Control Specialist
Send us your element data, electrical supply and furnace requirements.
Call 01323 811 100 or submit your application details today.
