Harry Ward Leonard was a very smart man who lived a long time ago. He liked to invent things that helped make electricity work better. You know, the stuff that makes your lights turn on and your TV work!
One of the things he invented was called the Ward Leonard system. This system helps control how much electricity is used by machines, like big motors. Imagine you have a toy car with a remote control. With the remote control, you can make the car go faster or slower. Well, the Ward Leonard system works in a similar way, but instead of a toy car, it controls big machines.
This is very important because if we didn't have a way to control how much electricity they use, it would be very hard to make sure there's enough power for everyone. It's kind of like when you're sharing a box of cookies with your friends. You want to make sure everyone gets some and nobody takes too many.
Thanks to Harry Ward Leonard and his invention, we can have more control over how much electricity we use and make sure there's enough for everyone who needs it.