Product category:
Stepper and Servo Drives, Motors, Controls
News Release from: Lenze | Subject: Safety Stop 9300 Servo Series
Edited by the Engineeringtalk Editorial
Team on 09 September 2002
Servo drive cuts costs without affecting
safety
The new Safety Stop version of the Lenze 9300 Servo Series has been developed to help machine and system builders cut costs, without affecting the operating safety of equipment.
The new Safety Stop version of the Lenze 9300 Servo Series has been developed to help machine and system builders cut costs, without affecting the operating safety of equipment where disconnection of the drive is a critical requirement Featuring a special safety disconnect switch within the drive unit itself, the new 9300 Safety Stop variant eliminates the need for separate contactors and improves EMC protection of the motor cable, by avoiding the need to interrupt the cable screening
This article was originally published on Engineeringtalk on 21 Feb 2000 at 8.00am (UK)
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Safety critical machinery often needs to be configured to ensure that the output from the drive to the motor can be disconnected instantly in the event of a fault.
This is typically achieved by inserting a contactor into the motor power line and, although this system normally works satisfactorily it can be prone to problems, as the contactors can wear, while the need to break the screened motor cable can result in unwanted interference from EMC emissions.
In addition, the extra component adds to the cost of installation, wiring and hardware and, in equipment where space is at a premium, can be hard to fit.
By comparison, the new Lenze Safety Stop variant is a compact and fully self-contained unit, incorporating a conventional transistor switch within the circuitry of a standard 9300 Series drive.
The Safety Stop variant is simply actuated by a 24V signal and, in the event of a fault, will automatically disconnect the power output to the motor.
The fault signal would typically originate from a PLC that has received an error signal or from machine guarding that has been opened.
The concept of the integrated safety switch complies with the requirements of EN954-1 and EN1037.
Perhaps as importantly, as there are no moving contacts, long reliable life is possible, while the fact that the motor power cable does not need to cut means that it is easy to meet EMC regulations.
In addition, the response time of the electrical circuit will, in many instances, be faster than that for a traditional contactor arrangement.
The Safety Stop variant of the 9300 Servo Series drives is available from stock up to 30kW, with a small surcharge above the standard drives, usually in the region of GBP 50-100 - a figure that more than offsets the normal additional cost of the contactor and installation. Request a free brochure from Lenze ...
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