Comments on: Ask an Electrician https://calrobot.com/2019/07/05/2541/ Thu, 30 Jul 2020 00:18:40 +0000 hourly 1 By: Jerry Bransom https://calrobot.com/2019/07/05/2541/#comment-107 Thu, 30 Jul 2020 00:18:40 +0000 http://calrobot.com/?p=2541#comment-107 Today I made a terrible mistake. I told a helper that 9 lead motors are always wired the same. I always say “For Hi Voltage (480v), Line1 to 1, Line2 to 2 & Line3 to 3 and tie 4to7, 5to8, 6to9. For Lo Voltage(208/240), Line1 to 1&7, Line2 to 2&8 & Line3 to 3&9 and tie 4,5&6 together”. Then of course the motor turned out to be a DELTA MOTOR, not WYE. 9-lead Motors can be WYE/DELTA (most common) or DELTA/DELTA (unusual). Of course the motor we were hooking up was DELTA/DELTA. That is my luck in the new age.

Luckily the Helper is smart and I re-examined my statement before he finished after he thought something was fishy. Sure enough, the wiring I said to use was wrong. For a 9-Lead DELTA/DELTA motor, “For Hi Voltage, Line1 to 1, Line2 to 2 & Line3 to 3 and tie 4to7, 5to8, 6to9. For Lo Voltage it is different, Line1 to 1,7&6, Line2 to 2,8&4, Line3 to 3,9&5”

I am not going to beat this to death. Journeymen make mistakes, especially when you rely on the motor wiring diagram being on the motor where I can check it. This motor had a really bad nameplate but I deduced enough information to determine it was DELTA/DELTA.

The real point here is the Helper deserves a good deal of credit for telling the journeyman (Politely) that “Something was rotten in Denmark!” Those kind of helpers are few and far between.

]]> By: Jerry Bransom https://calrobot.com/2019/07/05/2541/#comment-103 Fri, 03 Apr 2020 01:27:28 +0000 http://calrobot.com/?p=2541#comment-103 I had an unusual event this week. We have several dead Rockwell VFDs on our shelf at the shop. Over the years this has been an ongoing problem with the maintenance we do. I switched to TB Woods a few years back (1991) because I could swap parts from one drive to another. Then my source for TB Woods drives convinced me to switch to Yaskawa (2001). We have been using the Yaskawa ever since. Lately we use the A-1000 drives for almost everything. But I also use another and I love those guys at Automation Direct, especially Dean. The tech support from those guys is unmatched by anyone, even Yaskawa. So I have as many Automation Direct drives out there as Yaskawa. I know I can get a drive the next day with them. Nobody else can do that!

Honestly, neither has failed until this week, we had one with an unusual CF3 fault. One day we would have it, the next day not. I decided to replace it. It was nearly 3 years old anyway. But what causes a drive like that to fail occasionally? CF3 fault means the power source is not even. But there was a 3 other drives in the same cabinet and they work great. I did a lot of wire checking and re-terminating. Took it apart looking for circuit board cracks. NOTHING

So it is at my office now. It was working when I removed it. “Bloody Ell” as Doug Mellor used to say. Anyone have similar experiences with drives? You can start working on them and 4 hours later you say “where am I?”

]]>