AN-1 High Surge Lock

LP-2 Operates High Surge Current Electric Lock

Figure 1 above shows an LP-2 and a RT-1 supplying power for a high surge current, 2 stage electric lock. The first stage of a typical vertical bar electric lock draws 16 Amps for about a ½ of second to unlock the door. After the initial surge from the first stage, the second stage holding current is about 300ma. Because the LP-2’s current is limited to 3 Amps, you must use either a standby battery or capacitor to supply the balance of the high current surge. After the surge the LP-2 will quickly recharge the storage device. The capacitor is used when no standby power is desired. The Electrolytic Capacitors can be obtained from or 

The heavy contacts of the RT-1 (see *RT-1HD note below) are used switch the high current locally to the door locks. Only a small control current goes back the access control panel.

The SN-1 is placed across the door lock to suppress interface and protect the LP-2 from the very high spikes generated from the electric lock.

Refer to Technical Sales Bulletins LP-2, RT-1, RT-1HD and SN-1 for more information.

*RT-1HD Note:  Our RT-1HD 12v or 24v Heavy Duty Relay has 40A rated form C contacts.  We recommend this over the RT-1 15A relay used above for good long term reliability.