Protection circuit for an electric motor with a single-phase winding, an electric centrifugal pump and an oil mist separator with such a protection circuit
AssigneeBühler Motor GmbH
InventorJens Weiss
Life of this patent
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Abstract
A protection circuit for an electric motor with a single phase winding, consisting of two coil sections with central tapping, wherein the two coil ends of the coil sections are each connected to ground via a switching element. The task of the invention is for an electric motor of this type to ensure a thermal relief for the switching elements, improved and smoother running, reduced warming of the printed circuit board, improved EMC characteristics, a more robust design of the overall switching, a focused conduction of the losses and an extra protection against any surge impulses from a mains network.
Claims12
A protection circuit for an electric motor powered by a voltage source, the motor having a single-phase winding which consists of two coil sections each having first and second ends, and a center tapping connected to the voltage source and to the first ends of the two coil sections, the protection circuit comprising:
- the second winding ends of the coil sections being connected to ground via a respective field-effect transistor, wherein a cut-off current of a coil section is dispersed via an electrical power component that is connected to the field-effect transistor in parallel, and
- an RC attenuator connected between the second end of one of the coil sections and the ground,
- wherein the field-effect transistor and a bipolar power transistor are thermally decoupled,
- wherein the electrical power component comprises the bipolar power transistor, so that each coil section is assigned the bipolar power transistor, and
- wherein the RC attenuator comprises a snubber network.
Dependencies are inferred from the claim text.