Apparatus for displaying thermal condition of motor controller
US5220478A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 1991 |
| Grant date | Jun 15, 1993 |
| Priority date | — |
| Expiry date | Apr 18, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/0935
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for remotely displaying information about heat in a motor having an associated motor-starting contactor with an overload relay system is provided. The apparatus includes a suitably programmed microprocessor which obtains a signal representative of current in the motor, squares the current and multiplies by time. This actual I.sup.2 t value is then used to calculate a signal representative of a relationship between the actual I.sup.2 t value and a target value at which the contacts of the motor-starting contactor will open due to an overload current situation. This relationship is preferably a percentage which is then displayed on either an LED bar type display or a digital display. The display may also include a "trip" indicator and a "reset allowed" indicator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.