Frequency converter for an immersion vibrator

1. A method of operating a machine driven by an electric motor electrically connected to receive a special voltage via a main plug, the method comprising the steps of:

receiving a mains supply voltage at a plug part of a portable frequency converter;

receiving an electrical plug part of the machine in an electrical socket of the portable frequency converter;

converting the mains supply voltage to the special voltage via a converter circuit of the portable frequency converter; and

communicating the special voltage to the machine via the electrical socket of the portable frequency converter and the electrical plug part of the machine.

2. The method of claim 1 , further comprising the steps of:

positioning a changeover switch at a first position so that the converter circuit converts the mains voltage received at the plug part of the frequency converter to the special voltage;

receiving the special voltage at the plug part of the frequency converter; and

switching a changeover switch from the first position to a second position in which the converter circuit passes through the special voltage received at the plug part of the frequency converter to the plug socket without modifying the special voltage.

3. The method of claim 1 , wherein a frequency level of the special voltage is higher than a frequency level of the mains voltage.

4. The method of claim 1 , wherein the machine is an immersion vibrator.

5. The method of claim 1 , further comprising the step of:

pulling the machine and the portable housing of the frequency converter using a protective sleeve, wherein the plug part of the machine is connected by a mechanical securing device to the plug socket of the frequency converter.

6. The method of claim 1 , wherein the main plug of the machine disconnects from the frequency converter and inserts into a special voltage network for receiving the special voltage.

7. In combination:

an immersion vibrator having a main plug configured to plug into a special voltage network so as to receive a special voltage; and

a frequency converter, including:

a mobile converter housing;

a converter circuit that is arranged in the converter housing and that converts an electrical mains voltage to the special voltage, the mains voltage having a frequency level lower than the special voltage;

a plug part;

a plug socket which is fed with the special voltage from the converter circuit, wherein the main plug of the immersion vibrator plugs into the plug socket; and

a changeover switch having a first position so as to cause the converter circuit to convert the mains voltage received at the plug part of the frequency converter to the special voltage for communication to the main plug of the immersion vibrator, and a second position so as to cause the converter circuit to pass through the special voltage received at the plug part of the frequency converter to the main plug of the immersion vibrator without modifying the special voltage.

8. The combination as claimed in claim 7 , wherein the frequency converter further comprises a securing device in the region of the plug socket, via which the plug part of the immersion vibrator is held in the plug socket.

9. The combination as claimed in claim 7 , wherein the converter housing has an elongated external shape with minimized transverse dimensions configured to withstand immersion in a liquid concrete.

10. The combination as claimed in claim 7 , wherein the converter housing has a smooth outer skin, and allows mobile handling of the frequency converter.

11. The combination as claimed in claim 7 , wherein the plug socket is connected to the housing via a supply cable.