Diverter Switch for On-Load Tap Changers | Electrical Component Directory

Product Specifications

Technical details and manufacturing context for Diverter Switch

Definition

The diverter switch is a critical component of on-load tap changers (OLTC) used in power transformers. It operates under load to change the transformer's voltage ratio by switching between different tap positions on the winding. This component ensures continuous power supply during tap changing operations by temporarily bridging two adjacent taps while the main contacts transfer the load. The diverter switch is designed to handle rated voltages from 12 to 40.5 kV, with special design required above 40.5 kV. Rated currents range from 200 to 1250 A, with higher currents increasing contact wear. Short-circuit withstand capability is 20 to 40 kA for 1 second, per IEC 60214-1. The number of positions varies from 8 to 35, depending on transformer design. Switching time is typically 0.03 to 0.06 seconds, with faster switching reducing arc duration. Mechanical life ranges from 300,000 to 800,000 operations, and electrical life from 100,000 to 300,000 operations at rated current, both per IEC 60214-1. Contact resistance is limited to ≤50 µΩ to prevent overheating. Operating temperature range is -40 to 85 °C, with oil viscosity issues below -40 °C. Degree of protection is IP54 to IP65 for outdoor enclosures, per IEC 60529. Insulation level is lightning impulse withstand of 75 to 200 kV. Weight ranges from 50 to 300 kg, depending on rating and design. Materials include copper alloy contacts, insulating oil, fiber-reinforced polymer housing, and stainless steel mechanical parts. The diverter switch operates by first making contact with the new tap position while maintaining contact with the old position through a transition resistor, creating a temporary parallel path that prevents current interruption. It then breaks contact with the old tap, completing the transition. The transition resistor limits circulating currents during switching. This component is essential for voltage regulation in power transformers, ensuring stable power delivery. When selecting a diverter switch, verify model-specific values and standards with the legal manufacturer or supplier, as the listed ranges are directory references and must be confirmed for the actual application.

Working Principle

During tap changing, the diverter switch first makes contact with the new tap position while maintaining contact with the old position through a transition resistor. This creates a temporary parallel path that prevents current interruption. The switch then breaks contact with the old tap, completing the transition. The transition resistor limits circulating currents during the switching process.

Common Materials

Copper alloy contacts, Insulating oil, Fiber-reinforced polymer housing, Stainless steel mechanical parts

Technical Parameters

Parameter	Typical range	Notes & selection driver
Rated Voltage	12–40.5 kV	Above 40.5 kV requires special designIEC 60214-1
Rated Current	200–1250 A	Higher current increases contact wearIEC 60214-1
Short-Circuit Withstand	20–40 kA	For 1 s, per standardIEC 60214-1
Number of Positions	8–35	Depends on transformer design
Switching Time	0.03–0.06 s	Faster reduces arc duration
Mechanical Life	300000–800000 operations	Higher for maintenance-freeIEC 60214-1
Electrical Life	100000–300000 operations	At rated currentIEC 60214-1
Contact Resistance	≤50 µΩ	Higher causes overheatingIEC 60214-1
Operating Temperature	-40–85 °C	Below -40 oil viscosity issuesIEC 60214-1
Degree of Protection	IP54–IP65	For outdoor enclosureIEC 60529
Insulation Level	LI 75–200 kV	Lightning impulse withstandIEC 60214-1
Weight	50–300 kg	Depends on rating and design

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Moving Contact Assembly
Transfers electrical connection between tap positions

Material: Copper-tungsten alloy
Fixed Contacts Part
Stationary connection points for each tap position

Material: Copper alloy with silver plating
Transition Resistor Part
Limits circulating current during switching

Material: Nickel-chromium alloy
Drive Mechanism
Provides mechanical force to move contacts

Material: Stainless steel
Insulating Housing Part
Provides electrical insulation and mechanical support

Material: Fiber-reinforced epoxy resin

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Tap Changer (if applicable)

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Tap Changer

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Manufacturers of Diverter Switch

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Frequently Asked Questions

What is the function of a diverter switch in a tap changer?

The diverter switch transfers load current from one tap to another without interrupting the circuit, allowing voltage ratio changes under load.

What are the typical rated voltage and current ranges for a diverter switch?

Typical rated voltage is 12 to 40.5 kV, with special design above 40.5 kV. Rated current ranges from 200 to 1250 A, per IEC 60214-1.

How does the transition resistor work during switching?

The transition resistor creates a temporary parallel path between the old and new taps, limiting circulating currents and preventing current interruption.

What standards apply to diverter switches?

IEC 60214-1 covers tap changer requirements, and IEC 60529 covers degree of protection. Always verify compliance with the manufacturer.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records.

Preliminary Technical Classification

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pressure:	Atmospheric to 2 bar absolute (sealed enclosure)
other spec:	Rated current: 100A to 3000A, Switching capacity: 10kA to 63kA, Mechanical life: 500k to 1M operations, Electrical life: 50k to 100k operations at rated current
temperature:	-40°C to +105°C (operating), -55°C to +125°C (storage)

Diverter Switch

Product Specifications

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