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Allows the elevator to return to a safe landing or signals a "slam stop" in the event of an earthquake

When elevator owners in earthquake-prone areas need to modernize their elevator systems to meet ASME/ANSI A17.1 earthquake code requirements, they discover that custom-built retrofit solutions tend to be exceedingly complex and labor-intensive. Electrodyn’s Earthquake Unit Model EQ is an efficient and economical alternative.

Model EQ provides two levels of safety—dual inputs capture seismic activity and/or counterweight displacement situations. Depending on the type of signals received, the unit will either return the car to a safe landing or signal a slam stop, as appropriate. In addition, in the event of counterweight derailment, intelligent logic moves the car away from the counterweight.


Interface relays in the Model EQ are matched to the control voltage and isolated from logic circuits. Installation is accomplished through a series of parallel and series connections between the Earthquake Unit and the host controller. The Earthquake Unit provides a wide range of dry contact configurations to produce the required functionality regardless of controller logic. Two sets of normally opened dry contacts activate the system. One set is provided by the seismic device, the other from the counterweight displacement device. Once either device is closed, even momentarily, the Model EQ requires manual resetting per ANSI code requirements.

Code Compliant

Model EQ is recognized nationally where applied in the US. If the elevator does not have this upgrade in regions where there is a fault line it can be catastrophic.

Complete Package

The Earthquake Unit comes complete with revised wiring diagrams and “pony sheets” for a step by step guide through the installation process. We also provide free technical support.


• 6.0”H x 11.0”W
• All relays are 4 pole with neon indicator lights and 5 amp contacts
• Relays connected in parallel with existing controller relays, saves controller spare contacts
• 1/8” thick printed circuit board with 2oz copper traces and 12,000 volt insulation
• Isolated interface relays enhance versatility
• Installation time: 8 hours

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