Purpose and application

PR-07 mechanisms are intended for manual operation of disconnectors and earthing (grounding) switches. Manufactured to GOST 689-90 (legacy reference) and, for English-language markets, aligned with EN/IEC 62271-102 and EN/IEC 62271-1. The PR-07 operates the contact blades or earthing switches of new-series disconnectors RDZ, RG, RLK, etc., for medium-voltage ratings up to 35 kV. PR-07 is supplied with one main shaft and one earthing-switch drive shaft.

Service conditions

Normal operation is ensured under the following conditions:

• altitude - up to 1000 m above sea level;
• upper ambient temperature - +40 °C;
• lower ambient temperature - -60 °C (for UHL1-type builds);
• precipitation, wind, dust and rime - within the environmental impacts for outdoor, unprotected locations per EN/IEC 60721-3-4;
• relative humidity - up to 100% at +25 °C (short-term), without condensation inside the mechanism enclosure;
• mechanical vibration levels - typical for substation equipment; shocks exceeding MV switchgear service norms are excluded;
• mounting on vertical or inclined structures with adjustable linkage geometry.

Exterior surfaces feature corrosion-resistant finishes (powder coating / zinc-plated parts depending on configuration) suitable for operation in moderate and cold climates. Design seals and cable glands provide the specified enclosure protection against rain, snow and dust.

Layout and design features

The mechanism consists of a housing, main output shaft, earthing-switch drive shaft, an interlocking device based on ZB-1M UHL1 electromagnetic lock, a cam-type switching mechanism, operating handle, and cable entries for interlocking and signalling circuits. The design emphasizes easy maintenance and high serviceability:

• Housing - metal, with a hinged drop-down cover. Access during installation and setting is provided after unlocking with a special key and lowering the cover. The interior has guides and mounting points for auxiliary contact blocks, terminal strips and kinematic elements.
• Output shafts - main and earthing - sized to transmit the rated torque with a 90° rotation. Shaft ends accept keyed/clamp joints for clamps, links and levers. An adjustable clamp on the output shaft enables precise alignment of OPEN/CLOSED positions with the apparatus shaft.
• Switching mechanism - cam-type, with spring-loaded detents to fix end positions; anti-backdrive elements prevent unintended movement.
• Auxiliary contact blocks (KSA) - provide discrete position signals for the main shaft (up to 12 contacts) and earthing-shaft (up to 4 contacts). Contact schemes support “dry” contacts or switched voltage for local annunciation/AMR per project.
• Operating handle - ergonomic, extendable. It is pinned in the horizontal position for operation and parked vertically after operation. In the vertical (parked) position, the handle can be padlocked (operational anti-tamper lockout).
• Electromagnetic interlock - based on ZB-1M. Without a permissive signal, the plunger remains locked, preventing rotation. When the permissive is applied, the plunger is released by the electromagnet key, allowing the operation.
• Cable entries - threaded (size per project) for sealed entry of 220 V DC interlock circuits and signalling wiring.

The linkage allows repositioning of levers and arm lengths to match various disconnector and earthing-switch types. Installation is possible on posts, base plates or directly on switchgear steelwork using standard fixing holes.

Safety and interlocking

Personnel safety is ensured by combined electrical and mechanical interlocks:

• ZB-1M electromagnetic interlock prevents operations unless permissive conditions are met (e.g., adjacent apparatus status). The design includes the lock, KEZ-1M electromagnetic key and KM-1 emergency magnetic key (for release per procedure). Interlock circuit nominal - 220 V DC.
• Inter-operation interlocks - implemented via the cam mechanism and KSA contacts: earthing-switch closing is blocked when the main disconnector is closed; only the sequence “OPEN disconnector → CLOSE earthing switch” is permitted.
• Handle mechanical lock - parking in the vertical position with padlock to prevent unauthorized access.
• Protective earthing - provision for connecting a grounding conductor to the mechanism housing via a designated terminal.

OPEN/CLOSED status to local mimic panels, operator panels or SCADA is transmitted via KSA contacts, simplifying integration into existing control-power schemes.

Versions and options

PR-07 is available in several configurations with options to tailor the mechanism to a specific project:

• orientation of output shafts and levers (left/right build; top/bottom link rod exit);
• clamps/couplings to mate with shafts of various diameters and profiles;
• extended handle/extension bar to reduce operator force (with total handle length ≤ 1.5 m the force does not exceed the specified value);
• expanded KSA contact sets, including paired contacts for redundant signalling;
• housing material and coating selection to match environmental corrosion severity;
• extended hardware and mounting bracket kits;
• cable glands sized to the required cable diameter/type (glands, sealing bushings);
• custom terminal and part marking per project schematics.

Standards compliance

The PR-07 design and service characteristics follow the requirements and terminology of the following standards:

1. GOST 689-90 - “AC disconnectors and earthing switches above 1 kV. General specifications” (legacy reference also covering drives and auxiliaries).
2. EN/IEC 60721-3-4 - classification of environmental conditions for stationary use at non-weather-protected locations (outdoor), applied here instead of GOST 15150-69 category 1 (UHL1).
3. EN/IEC 62271-102 - “High-voltage switchgear and controlgear - Part 102: Alternating-current disconnectors and earthing switches”.
4. EN/IEC 62271-1 - “High-voltage switchgear and controlgear - Part 1: Common specifications”.
5. EN/IEC 60529 (IP code) - “Degrees of protection provided by enclosures” - for enclosure selection per project.

Available versions and options (for design and ordering)

Engagement with manufacturers and contractors