Motor control circuit
US4121140A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 4, 1977 |
| Grant date | Oct 17, 1978 |
| Priority date | — |
| Expiry date | Mar 4, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P1/44
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A motor control circuit for preventing automatic restarting of an electric motor following an interruption of electric current flow therethrough. An electric motor incorporates winding means and a series automatic reset thermal overload protector. Current flow to the motor is normally controlled by current supply switch means in series with the motor across electric power input terminals. A first relay device is switched by external actuation of a normally open start switch to switch the current supply switch means to its conductive state for starting the motor. A second relay device connected across a pair of motor terminals is energizable in response to current flow through the motor. A restart prevention switch connects in series with the current supply switch and motor across the electric power terminals. The restart prevention switch is coupled to both the first and second relay devices and is controlled thereby for permitting current flow to the motor therethrough either while the start switch is being actuated, or while the motor is operating, the restart prevention switch otherwise being in its current blocking state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.