My situation is as follows: I have 2 A-B 523 VFDs that are each supplied 3 phase voltage through 2 contactors pulled in 3 seconds apart with a MicroLogix 1000 upon initial startup. In the event of a power disruption, I want to allow at least 2 minutes to lapse before the drives are able to re-energize to protect the drive. Re-energizing the drives too quickly can damage the drives.
So... I have 2 TONs (1 set for 3 seconds, 1 set for 6 seconds) and they sequence the contactors in 3 seconds apart. This is used for initial start up (say, when coming in at the beginning of the day)
What I need help with is putting in a 3rd timer: it should not allow a start up after a power outage until 2 minutes have lapsed. If more than 2 minutes of power outage has occurred, enough time has lapsed due to the power outage itself, and it should resort to the start up of 3 and 6 seconds.
Any thoughts? I thought about MOV statements along with timers but I'm open to any suggestions.
So... I have 2 TONs (1 set for 3 seconds, 1 set for 6 seconds) and they sequence the contactors in 3 seconds apart. This is used for initial start up (say, when coming in at the beginning of the day)
What I need help with is putting in a 3rd timer: it should not allow a start up after a power outage until 2 minutes have lapsed. If more than 2 minutes of power outage has occurred, enough time has lapsed due to the power outage itself, and it should resort to the start up of 3 and 6 seconds.
Any thoughts? I thought about MOV statements along with timers but I'm open to any suggestions.