Method and system for stopping elevators

• US 20070187185A1
• Filed: 01/25/2005
• Published: 08/16/2007
• Est. Priority Date: 01/30/2004
• Status: Active Grant

• Current Assignee: Danfoss A/S
• Original Assignee: Danfoss Drives A/S (Danfoss A/S)
• Inventors: Abraham, Detlev, Mennen, Hans-Josef
• Granted Patent: US 7,775,327 B2
• Time in Patent Office: Days
• US Class Current: 187/288
• CPC Class Codes: B66B 1/308 with AC powered elevator drive
• CPC Class Codes: B66B 5/0031 for safety reasons

Abstract

The invention relates to methods for stopping elevators especially when using at least one three-phase motor operated by a static frequency converter. According to the invention, a brake relay controls the brake of the motor such that releasing of the brake relay causes the motor to be decelerated while the brake relay is coupled to a protective circuit in such a way that the control pulses required for generating the driving motor field are safely blocked when the brake relay is released.

Claims

1. A method for stopping elevators, particularly by using at least one AC motor driven by a static frequency converter, in which a brake relay controls the brake of the motor so that de-energising the brake relay (6) will brake the motor, the brake relay being connected with a safety switch in such a manner that de-energising the brake relay will reliably block the control impulses required for generating the driving motor field.

2. The method according to claim 1, in that wherein a series-connected power semiconductor will disconnect faster than the contact of the brake relay used to control the brake.

3. The method according to claim 1, wherein if a safety system is triggered, a call will control the brake relay so that it is pulled in.

4. A system for implementation of the method according to claim 1, comprising an elevator safety circuit with preferably series-connected safety systems, acting via the elevator control upon the brake relay located in a frequency converter, said brake relay controlling the brake of the motor, the frequency converter comprising a frequency converter logic unit that produces control signals, used by the motor control power semiconductors contained in the inverter, for a rotating-field-producing pulse pattern, and a safety switch, which is on the one side connected to the brake relay and on the other side to the power semiconductors, so that de-energising the brake relay will disconnect the torque-generating, rotating field of the motor.

5. The system according to claim 4, wherein the brake relay used is an emergency-out relay, preferably conforming to EN 954-1, category 4.

6. The system according to claim 4, in that wherein only one brake relay is provided.

7. The system according to claim 4, wherein the frequency converter is located in the connection box or in the housing of the elevator motor.

8. The system according to claim 4, wherein the contact of the brake relay controlling the brake is connected in series with a power semiconductor.