I have a customer who experienced a drive failure of a Yaskawa F7 VFD due to a lightning strike. He stated he wanted a brand new exact replacement installed, but this drive is obsolete and discontinued. He was adamant about the F7 model because he has several identical machines and wants to keep them all identical, not have one with a different drive retrofitted. So I purchased an F7 drive off Ebay, still brand new, sealed in the original box, and upon opening it discovered the production date stamp reads 2007. I have reformed capacitors on old stock drives before, but nothing nearly as old as this. I consulted several manufacturers whitepapers on VFD capacitor reforming and they all give clear guidance up to about 4 years of age, and after that the details get vague. It's a 480V drive and Right now I have it powered up on 120V single phase for about 15 minutes so far, no smoke. I'm planning to leave it there for about 2hrs and then graduate to 240V for 2-3 hours and then 480V overnight, then go install it in the morning if it's still alive.
Does that sound like a good plan? If it survives the night, do you expect it will survive the test of time once installed? Any better ideas? I'm wondering if it's a better bet to remove the DC bus caps from the original drive and install in the new drive tomorrow onsite. Obviously it would be better to install brand new caps, but they don't sell those at Home Depot and this is a bit of time-sensitive issue.
Does that sound like a good plan? If it survives the night, do you expect it will survive the test of time once installed? Any better ideas? I'm wondering if it's a better bet to remove the DC bus caps from the original drive and install in the new drive tomorrow onsite. Obviously it would be better to install brand new caps, but they don't sell those at Home Depot and this is a bit of time-sensitive issue.