Three-Phase Main Switch 12A Schurter Amazonas

Switch 42501 is a three-phase main switch for the Kranzle pressure washer with a 400V motor, manufactured by Schurter in the Amazonas series. It serves two functions simultaneously: it allows the operator to switch the washer on and off, and contains a built-in overcurrent protection with a threshold of 12A per phase. When the motor current exceeds this value on any phase, the trip mechanism permanently deactivates the switch – with no reset function. Activation of the protection means the entire switch must be replaced. The 12A value refers to phase current – lower than the current drawn by an equivalent single-phase 230V motor, which is characteristic of three-phase 400V supply.

Application

The switch is mounted in the washer control panel as the main component for engaging the three-phase 400V motor power supply. During normal washer operation, the current drawn by each motor phase stays below the 12A threshold – the switch operates only as a switching device. Under motor overload (seized pump, dry running, damaged bearings), the phase current exceeds 12A and the trip permanently deactivates the switch, protecting the motor windings from thermal damage.

Replaced when mechanically damaged, unresponsive to switching, or after the built-in overcurrent protection has tripped.

Symptoms – when to replace

• The washer does not start despite an intact three-phase 400V supply and no other faults – the switch does not close the circuit when toggled.
• The switch tripped after motor overload and does not restore power despite returning to the on position – the built-in protection has permanently deactivated the switch.
• Mechanical damage to the housing – cracked rocker, blocked movement or loose switch in the panel slot.
• Burnt or melted electrical terminals – the result of arcing from loose connections or repeated overloads.
• No circuit continuity on one or more phases when measured with a multimeter in the on position.

How to select the right part

Rated current of 12A per phase and three-phase power supply are critical parameters. A three-phase switch handles all three phases simultaneously – when the protection trips on one phase, all three are disconnected at the same time, protecting the motor from running on an asymmetric supply.

When ordering a replacement, confirm the identical rated current of 12A, three-phase supply type and housing type – mounting dimensions must match the panel aperture of the washer. Before replacing the switch, make sure the cause of the trip is not a permanent motor overload.

Compatibility

Three-phase main switch with built-in overcurrent protection for Kranzle pressure washers with a 400V motor. Rated current: 12A per phase. Manufacturer: Schurter, Amazonas series. Requires replacement after protection trips – no reset function. Verify the exact compatibility range by reference number 42501.

[faq]

What happens when a three-phase switch trips – does it disconnect all three phases simultaneously?|Yes – a three-phase switch disconnects all three phases simultaneously when the protection trips. This is intentional: a three-phase motor running on two phases instead of three (so-called single-phasing) causes rapid winding overheating and is more damaging than a complete power disconnection. The Amazonas trip mechanism switches off all three poles through a single trip element.

The switch tripped under motor overload – how to check the cause before replacing switch 42501?|After replacing the switch, measure the current drawn by each of the three phases during normal operation with the gun open – it should be clearly below 12A and symmetrical across all phases. Asymmetry between phases indicates a supply problem (missing phase, unequal voltages) or a motor fault (damaged winding). Excessive current on all phases points to mechanical pump overload or worn motor bearings.

How does three-phase switch 42501 differ from single-phase switch 411107 – can they be used interchangeably in similar washers?|No – these are components for completely different power supply systems. Switch 411107 handles one single-phase 230V circuit; switch 42501 handles three 400V phases simultaneously. A washer with a three-phase 400V motor requires the three-pole switch 42501 – fitting single-phase switch 411107 in its place is technically impossible (different number of poles and terminals) and dangerous.

[/faq]