A frequency converter (inverter) with a standard torque-limit function is used for reliable starting of a multistage extractor with an induction motor. The proposed design of the multistage extractor was tested on a production bench; no failures caused by fault of the magnetic clutch were detected. Keywords: multistage centrifugal extractor, magnetic clutch, half coupling, mismatch angle of half couplings, frequency converter. Extraction technologies are important links in production processes in the chemical and radiochemical industries. Centrifugal extractors, the use of which makes it possible to ensure significant improvement in mass-exchange characteris- tics of the process, acceleration and optimization of the process, and compact arrangement of extraction equipment make up a separate group in the equipment layout of these production processes. An important characteristic of the extractors is short contact time between the effective solution and organic extractant. Use of centrifugal extractors in radiochemical production had, until recently been suppressed by the destructive action of radioactive radiation on seals, lubricants, and the electric motor. The problem of developing centrifugal extractors with high mass-exchange characteristics for operation under condi- tions of radioactive radiation is therefore critical. Multistage centrifugal extractors consist of several extraction stages (cells). Until recently, such extractors had not been used in the radiochemical industry. Let us examine a vertical hermetic multistage centrifugal extractor with a magnetic clutch. In comparison with single-stage extractors (1), which are connected in series, the advantage of a multistage extrac- tor is that there are no solution-transfer systems along pipelines from one stage to another, making it possible to increase the purity of the solutions. A vertical arrangement of the stages on a single shaft allows for simplification of the extractor design, a significant reduction in the number of drives (electric motors) in the extraction unit (particularly, for a large number of stages), and a reduction in the cost of the extractor. Alternative designs of multistage centrifugal extractors are being developed for solution of this problem, where an induction motor and the support subassemblies of the rotor are built on slip bearing formed from silicated graphite. Airtight- ness of the extractor is ensured by the use of a magnetic clutch in the drive, which transfers the torque from the driving half coupling to the driven half coupling via a separating partition (shield) that hermetically separates the effective recess of the extractor from the surrounding medium (2). When a cylindrical magnetic clutch is used in the design of an extractor, the following two alternate schemes are possible.