Handheld grinder with brushless electric motor
US11597050B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 2019 |
| Grant date | Mar 7, 2023 |
| Priority date | — |
| Expiry date | Dec 24, 2041 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K9/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power tool is provided including a motor case and a handle portion. An electric motor having a drive shaft is mounted within the motor case. A circuit board is disposed in the handle portion to accommodate a motor drive circuit. The motor drive circuit includes a rectifier configured to receive an alternating current from an alternating current (AC) power source and convert it to a direct current supplied to a DC power bus, and a bridge circuit having motor switches connected between the rectifier and the electric motor. A bus capacitor is mounted on the circuit board and coupled across the DC power bus. An auxiliary capacitor having higher capacitance than the bus capacitor is switchably coupled across the DC power bus. The handle portion includes a support member protruding radially outwardly to accommodate the auxiliary capacitor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.