Induction Motor Starters

<...automatic star delta starter...>

• will contain timers and interlocks, so that it all starts from a single electrical control signal.

<...normal star delta starter...>

• will have a multi-position control: "star - off - delta", that is operated by hand. They can still be found though they are becoming less commonplace.

Huh, I didn't know anyone ever did a manual transition like that. Seems odd really, the potential for a damaging transition spike would be exponentially higher.

Here in the US, we (used to) have a type of starter called a "manual compensator" which was essentially a manually controlled reduced voltage autotransformer (or primary reactor) motor starter. You had a handle on the side and pushed it one way to start with reduced voltage, then shifted the handle the other way to go full voltage (DOL) "when she sounded about right" as the old timers would put it. I still see one every now and again, but I don't think anyone uses them much any more. The "art" of knowing when to shift it is becoming an anachronism.

But I have never seen a Star-Delta controller that operated that way. Entirely possible, but why? To eliminate the cost of 1 timer?