GB575496A - Protection of three-phase motors - Google Patents
Protection of three-phase motorsInfo
- Publication number
- GB575496A GB575496A GB500344A GB500344A GB575496A GB 575496 A GB575496 A GB 575496A GB 500344 A GB500344 A GB 500344A GB 500344 A GB500344 A GB 500344A GB 575496 A GB575496 A GB 575496A
- Authority
- GB
- United Kingdom
- Prior art keywords
- motor
- plate
- contacts
- bimetallic
- curvature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H77/00—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting
- H01H77/02—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism
- H01H77/04—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrothermal opening
Landscapes
- Protection Of Generators And Motors (AREA)
- Thermally Actuated Switches (AREA)
Abstract
575,496. Thermal switches. WOODS OF COLCHESTER, Ltd., and DALY, B. B. March 17, 1944, No. 5003. [Class 38 (v)] A thermal switch for protecting a three-phase motor comprises a dished bimetallic plate normally bridging three contacts which reverses its curvature when heated. A fixed contact 3 of nickel-alloy having a lug 4 is located in each of the three ribs 2 of a perforated insulating base 1 in the centre of which is screwed the threaded end 5 of a stem 6 which carries a bimetallic disc 7. This disc 7 carries contacts 8 which may be of silver and normally engage and thus connect together the fixed contacts 3 to form the star-point of the windings of a motor. The switch may be fixed to the endplate of the motor by bolts passing through holes 14 which also secure the cap 9 against which is pressed a push button 10 by a spring 11. Heat from the motor or a resistance carrying the motor current causes the bimetallic plate 7 to reverse its curvature and break the circuits on overload. On fall of temperature the plate may be reset by depression of the push button 10, or by self-restoration, the plate being constructed as described in Specification 260,846, [Class 135]. A modification is described suitable for mounting within the motor housing, Fig. 4 (not shown).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB500344A GB575496A (en) | 1944-03-17 | 1944-03-17 | Protection of three-phase motors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB500344A GB575496A (en) | 1944-03-17 | 1944-03-17 | Protection of three-phase motors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB575496A true GB575496A (en) | 1946-02-20 |
Family
ID=9787892
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB500344A Expired GB575496A (en) | 1944-03-17 | 1944-03-17 | Protection of three-phase motors |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB575496A (en) |
-
1944
- 1944-03-17 GB GB500344A patent/GB575496A/en not_active Expired
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