INDUCTION ELECTRIC MOTORS, EXPLOSION-PROOF, WITH SQUIRREL-CAGE ROTOR, VA- AND VRA- SERIES.

Induction electric motors, explosion-proof, with short-circuited rotor, VA series, are designed for driving mechanisms in chemical, gas and oil-producing, as well as allied, industries where explosive mixtures of gas and steams with air (of T1, T2, T3, T4 categories by the GOST 12.1.011 standards) may be formed. In areas with high explosion likelihood the motors are to be used as required by the Article 7.3 PUE-86

Induction electric motors, explosion-proof, with short-circuited rotor, VRA series are intended for driving mechanisms in mining and allied industries where explosive mixtures of gas and steams with air (of T1, T2, T3, T4 categories by the GOST 12.1.011 standards) may be formed.

The VA- and VRA-series motors are intended for a long-duration operation in the S1 mode (GOST 28173 standards). Operation in the S2 - S7 modes is also permitted. The ratings may vary according to the table. The noise level tolerance is + 3 dB(A)

Induction electric motors of VA and VRA series meet the standards requirements as specified in the table

• ratings and performance data (GOST 28173).
• ranges of power, voltage and frequencies (GOST 12139).
• installation and overall dimensions (GOST 18709).
• classification of protection levels (GOST 17494).
• methods of cooling (GOST 20459).
• installation design (GOST 4541).
• noise-levels permitted (GOST 16372).
• vibrations permitted (GOST 20815).
• heat resistance assessment of insulation systems (GOST 8865).

Besides the above mentioned general standards, the explosion-proof electric motors of VA and VRA series meet the following requirements specified in the state standards:

• GOST 12.1.010 Explosion-protection. General requirements.
• GOST 12.2.020 Explosion-proof electric equipment. Terminology. Classification. Marking.
• GOST 12.1.011 Explosive mixtures. Classification and methods of testing.
• GOST 22782.0 Explosion-proof electric equipment. General technical requirements and methods of testing. Technical requirements and methods of testing.
• GOST 22782.6 Explosion-proof electric equipment with "Explosion-proof sheath" type of explosion protection.
• Rules of installation for electric devices (PUE-86).

By the degree of explosion protection, the VA and VRA motors are explosion-proof against explosive mixtures of IIB (degree of explosion protection 1ExdllBT4) and have enhanced security against explosion for mixtures of IIC-categories (degree of explosion protection 2ExdllCT4).

The motors are designed for operation at altitudes below 1000 meters above sea level, otherwise the load on the motor should be reduced as shown below:

The motors can operate with vibration caused by outside sources with acceleration of 0.5g at frequencies below 35 Hz.

Electric motors of VA and VRA series are designed for operation at AC 50Hz. Motors may be manufactured for 380V with the phases triangle-linked or for 660V with the phases star-linked. On request, motors may be manufactured for other standard voltages and the 60Hz frequency.

The motors may operate at voltage and frequency deviation limits specified by GOST 28173 (IEK 34-1).