{"id":2844,"date":"2026-05-12T01:00:00","date_gmt":"2026-05-12T01:00:00","guid":{"rendered":"https:\/\/shieldhz.com\/?p=2844"},"modified":"2026-05-09T10:46:32","modified_gmt":"2026-05-09T10:46:32","slug":"rotary-cam-switch-positions-poles-contact-stages","status":"publish","type":"post","link":"https:\/\/shieldhz.com\/ar\/rotary-cam-switch-positions-poles-contact-stages\/","title":{"rendered":"\u0634\u0631\u062d \u0645\u0648\u0627\u0636\u0639 \u0645\u0641\u0627\u062a\u064a\u062d \u0627\u0644\u0643\u0627\u0645\u0627\u062a \u0627\u0644\u062f\u0648\u0627\u0631\u0629 \u0648\u0623\u0642\u0637\u0627\u0628\u0647\u0627 \u0648\u0645\u0631\u0627\u062d\u0644 \u0627\u0644\u062a\u0644\u0627\u0645\u0633"},"content":{"rendered":"

A rotary cam switch controls multiple circuit paths through a single actuator by rotating precision-machined cam discs against stacked contact carriers. Three parameters define what any given switch can do: positions (the number of detent stops), poles (the number of independent circuits switched simultaneously), and contact stages (the number of stacked contact modules on the shaft). Getting these three parameters right before ordering is the difference between a panel that works first time and one that requires a costly redesign. This article explains each parameter, shows how to read a contact chart, walks through common configurations, and gives you a practical checklist for selection, wiring, and procurement.<\/p>\n

\"Rotary
Figure 1. Positions describe detent stops, poles describe independent circuits, and contact stages describe stacked cam modules.<\/figcaption><\/figure>\n

Positions, Poles, and Contact Stages: Core Definitions<\/h2>\n

These three terms are distinct and frequently confused in specifications and purchase orders.<\/p>\n

\u0627\u0644\u0645\u0646\u0627\u0635\u0628<\/strong> are the discrete detent stops the actuator shaft can occupy. A 3-position switch has three mechanically stable states, each held by a spring-loaded detent. Common position counts are 2, 3, 4, 6, 8, and 12, with angular increments of 30, 45, or 60 degrees between stops depending on the switch series. The exact angular spacing and total rotation arc for a given model must be confirmed from the manufacturer datasheet.<\/p>\n

\u0627\u0644\u0623\u0639\u0645\u062f\u0629<\/strong> are the number of electrically independent circuits the switch controls in a single mechanical operation. A 4-pole switch opens or closes four separate circuit paths simultaneously. Each pole has its own contact bridge and is electrically isolated from adjacent poles. Rated insulation voltage between poles is a datasheet value — do not assume it from the series name alone.<\/p>\n

Contact stages<\/strong> (also called contact layers or decks) are the individual cam disc and contact carrier assemblies stacked axially along the shaft. Each stage contains one set of contact bridges per pole. Stacking multiple stages allows each stage to carry a unique cam lobe profile, so different circuits can open and close in different sequences across the same set of positions. A single stage typically handles one or two poles; a multi-stage assembly can manage a larger number of independent contact pairs.<\/p>\n

A useful way to hold the distinction: positions describe the actuator, poles describe the electrical width of a single switching event, and contact stages describe the mechanical depth of the switch assembly.<\/p>\n

For a practical introduction to how these switches are constructed and applied, see What Is a Rotary Cam Switch<\/a>.<\/p>\n

How the Cam Mechanism Controls Contact State<\/h2>\n

Each cam disc is a hardened profile mounted coaxially on the actuator shaft. Raised lobes and recessed valleys on the disc correspond directly to the open and closed state of the contact bridge at each position. When a lobe bears against a contact carrier, it lifts the contact bridge away from its fixed counterpart, opening that pole. When the shaft rotates to place a valley under the carrier, the spring drives the bridge closed.<\/p>\n

Stacking multiple cam discs along the same shaft — each with a unique lobe profile — is what gives a rotary cam switch its ability to sequence different circuits at different positions. This is a critical requirement in star-delta motor starters and reversing contactor circuits, where specific poles must open before others close to prevent a phase short circuit. The contact chart supplied by the manufacturer encodes exactly which poles are open or closed at each position, and matching that chart to your circuit’s switching requirements is the fundamental step in correct specification.<\/p>\n

Contact resistance across a properly wiped silver-alloy bridge is a datasheet value that should be confirmed before specifying the switch for low-signal or sensitive control circuits. If cam profile wear allows incomplete contact closure, resistance rises and circuit behavior becomes unreliable. Inspect contact bridges at the maintenance intervals specified in the product documentation.<\/p>\n

IEC 60947-3:2020+AMD1:2025 applies to switches, disconnectors, switch-disconnectors, and fuse-combination units for distribution and motor circuits, with rated voltage up to 1000 V AC or 1500 V DC. The standard sets requirements for rated insulation voltage, making and breaking capacity, and mechanical endurance. The current consolidated edition is available directly from the IEC webstore<\/a>. For a plain-language summary of how the standard applies to cam switch selection, see What Is IEC 60947-3<\/a>.<\/p>\n

Practical notes for cam mechanism maintenance:<\/p>\n