L25-202Y Centrifugal Switch Board for Electric Motor — order in Moldova

Technical specifications

Part number breakdown: the number after the letter “L” in the model name indicates the mounting bore diameter for the rotor shaft, in millimetres (25 mm in this case). The last digit before the letter in the part number indicates rotation speed: “2” corresponds to two-pole motors at 3000 RPM, “4” to four-pole motors at 1500 RPM.

Design features

• Metal board housing — provides mechanical strength and vibration resistance during motor operation.
• 25 mm mounting bore — sized to fit a rotor shaft of the corresponding diameter; a critical parameter when selecting a replacement.
• Lightweight construction (≈80 g) — adds negligible extra load to the rotor shaft during rotation.
• Simple mechanical design — fewer moving parts reduce the likelihood of failure compared to electronic starting relays.
• Compatibility with standard single-phase motors — used in both household equipment (sewing machines) and compressor equipment with single-phase drive.

Installation recommendations

1. Before replacement, always disconnect the electric motor from power and let it come to a complete stop.
2. Check your motor’s rotor shaft diameter against the board’s mounting diameter (25 mm) — a size mismatch makes installation impossible.
3. Determine the required rotation speed (3000 or 1500 RPM) from the marking on the removed part or the motor’s nameplate data before ordering a replacement.
4. When removing the old board, note or photograph the wiring and contact layout to correctly connect the new part.
5. Mount the board on the shaft strictly according to the mounting position, without misalignment, to avoid run-out during rotation.
6. After installation, check the free movement of the centrifugal mechanism by hand (before applying power) — the weights should swing out and return to their initial position freely.
7. After connecting power, check the motor’s operation at idle — the absence of unusual noise and a stable rise to running speed indicate correct installation.

Comparable solutions

Centrifugal switches in this line are marked using a consistent scheme: the letter L + shaft diameter in mm + a rotation-speed code. When selecting an equivalent, the key factors are shaft diameter and rotation speed, not just the exact part number:

Expert comment: always measure the actual shaft diameter with calipers before ordering, rather than relying solely on the old part’s marking if it’s worn or illegible — even a 1–2 mm error makes installation impossible without modifying the mounting location.

Common installation mistakes

• Selecting a board based on model name alone, without checking the actual shaft diameter — risk of receiving a part that physically doesn’t fit the shaft.
• Installing a board with the wrong rotation speed (e.g., L25-204 instead of L25-202Y) — the motor may fail to reach the required speed, or the starting winding may not disconnect on time.
• Mounting the board at an angle on the shaft — leads to run-out and premature mechanism wear.
• Incorrectly wiring the board’s contacts without first recording the old part’s wiring layout — risk of the starting winding malfunctioning.
• Skipping the free-movement check of the mechanism before applying power — can result in permanently closed or open contacts on the starting winding.

Practical use cases

• Small and medium single-phase compressors — the motor’s starting component at auto service centres, workshops, and small production sites.
• Sewing and embroidery equipment — a standard application for centrifugal switches in this line.
• Repair and refurbishment of electric motors in household and semi-industrial equipment — replacing worn or burnt-out boards during scheduled maintenance.
• Spare parts stock for service workshops maintaining single-phase electric motors across various equipment types.

Expert opinion

“A centrifugal switch is a simple mechanical part, but it determines whether a single-phase compressor motor starts at all. Often, when a compressor fails, the cause turns out to be this assembly rather than the motor itself. When ordering a board, I always advise customers in Moldova to first measure the shaft diameter with calipers and confirm the motor’s rotation speed — this rules out selection errors and unnecessary equipment downtime,” — Vitali Boluchevski, lead engineer at Acvatron SRL.

FAQ

What does the L25-202Y designation mean? “L25” indicates the mounting bore diameter for the rotor shaft — 25 mm, while “202” indicates the rotation speed of 3000 RPM (two-pole motor).

Is this board suitable for a single-phase compressor? Yes, centrifugal switches in this line are used in single-phase electric motors, including drives for household and semi-industrial compressors.

How do I know it’s the centrifugal switch that needs replacing, not the motor itself? A typical sign is that the motor hums but doesn’t reach speed and doesn’t start, while the starting winding fails to disconnect on time or doesn’t engage at all.

Can the board be replaced with a model of a different shaft diameter? No, the board’s mounting bore diameter must exactly match the rotor shaft diameter — a mismatch makes installation impossible without modification.

What’s the difference between “Y” and “S” suffixes in the part number? Different manufacturers may use different letters to denote board design variants; when selecting an equivalent, focus primarily on the shaft diameter and rotation speed listed in the specifications.