6. Are there any disadvantages to a Steinmetz circuit?

The Steinmetz circuit is intended as a kind of emergency solution for households without a three-phase connection or for machines where you want to save yourself the effort of wiring with three external conductors. The area of application is machines in which a rotational movement at a constant speed should be generated as cheaply as possible. The disadvantage of the Steinmetz circuit is that the starting torque is limited to ⅓ of the motor's nominal torque. To achieve the same performance, you have to use a larger engine, which is more expensive and takes up more space. Additionally, the efficiency is quite low at around 70%. For economic reasons, the Steinmetz circuit was always limited to motors with an output of less than two kilowatts. With the advent of three-phase frequency converters, the area of application was further restricted, as they can generate the three-phase three-phase current required for a three-phase motor from direct or alternating voltage. This makes it possible to operate a three-phase motor on just one external conductor without any restrictions. Three-phase motors in a stonemason circuit are used, for example. B. to drive concrete mixers, older washing machines and circulation pumps in heating systems. However, capacitor motors are often used there due to their simplicity.