Help needed: Two Automation Issues

As far as frequency protection: Check out www.falconups.com, they offer an online ups that takes incoming line voltage and uses it to basically charge a battery, then it uses battery voltage to generate AC voltage at a set frequency (60 Hz for example). We use these for our very sensitive lab equipment where flutuations in line power quality gives errors on our tests. Hope this helps, bear in mind this is a sad attempt at explaining this UPS, check out the website for an in depth explanation.

First, have you verified that when the charging relay switches off, the battery maintains a high enough voltage to keep the LM324 deactivated? Most battery charging circuits, including the ones we have designed for use with Sealed Lead Acid batteries at the company I work for, use hysteresis to ensure that when you disconnect the charging source, the charger will not turn back on until you have actually drained the battery down a little bit. Temperature compensation is also important.

Tim Kirk
tkirk@rogue-engr.com
Rogue Engineering Inc.

there is udedicated frequency relays which is used for detecting the df/dt ratings. use it and get your problem solved.

use two such relays. For one u set the low set(LS) frequency df/dt setting point and for the other high set(HS) df/dt setting point.

work with the potential free ops.

bye

Rabindra.

Mumbai, INDIA.