IPVMU Certified | 08/19/15 09:18pm
I take it the strikes are just switched by the controller, not powered by it? If so, is the access system also backup powered?
Do they normally draw power from a big power supply somewhere?
Also, they release when power drops? Because that fail-safe behavior can often be changed in the field in many strikes.
IPVMU Certified | 08/19/15 09:38pm
Yes they are just switched by the controller. Access system has its own battery backup. The strikes are powered by a separate 24VDC power supply. They don't release when power drops but that's not the intention. The client would like doors to be secure but operational during power outages; they should operate as normal even when power is out. Thus the need for backup batteries.
Brad, instead of having a module failover, couldn't you put the 24DC supply on a UPS?
Apologies if I'm being ignorant...
LONG Building Technologies | 08/19/15 10:26pm
Typically this would be done with a lock power supply with battery backup built into it, like an Altronix AL600ULX, or a LifeSafety Power. You can add as many pairs of batteries in parrallel (in additional enclosure if need be) to achieve the run time you need.
IPVMU Certified | 08/19/15 10:53pm
Thanks for all the responses guys. The dilemma is that the electricians were going to tie this in to the generator but it's maxed out. The PSU for the strikes is already wired in and there's no need to buy another a la the Altronix or similar. 24VDC output on locally stocked UPS seems to be difficult to find.
Possible solution: I'm going to use a 24VDC UPS controller (about 80 bucks) and a couple of 12VDC 7Ah batteries wired in series in an enclosure between the existing PSU and the Keyscan panel. Since the draw on each strike is rated at 190mA and only for about 1/4 sec I should have a pretty reasonable amount of battery backup time. I just need to pick the voltage point on the controller where power switches from main inputs to battery inputs.
IPVMU Certified | 08/20/15 01:44am
Yes it will recharge them.
IPVMU Certified | 08/20/15 03:01am
2 factors I guess:
1. A UPS with 24VDC output is not a stocked item with any of my distributors.
2. The relative ease of doing things the other way; different voltage thresholds are available
from the manufacturer and delivery is super quick. We have enclosures and
batteries in stock. The installation area would require the UPS to be in an
enclosure much larger than the one for the controller and 2 batteries.