Electrical circuit arrangement for the protection of presses

US4648003A · kind A · utility

Assignee

• L. Schuler GmbH · DE

Inventors

• Helmut Braitinger · Göppingen, DE
• Gunther Grupp · Eislingen/Fils, DE

Key dates

• Filing date: Jan 31, 1985
• Grant date: Mar 3, 1987
• Expiry date: Jan 31, 2005

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S388/903
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A protective circuit arrangement of a motor control for the starting and operation of a motor of a press with a power stage, a current-regulating element and a rotational speed regulating element. Comparator stages are connected to the inputs of the regulating elements for forming the guide magnitudes from the actual current value and the desired current value as well as from the actual rotational speed value and the desired rotational speed value. For suppressing the disconnect signal during the starting phase of the motor, the circuit additionally includes a rotational speed comparator stage, a desired current value memory and a current comparator stage. The desired current value, which stored after the starting phase in the desired current value memory, is compared with the current value in the current comparator stage to produce a motor current interrupt signal in case of an overload current that might lead to a press damage. As a result thereof, the damage is limited to the part responsible for the increased motor current.