Why is my blower motor drawing 12 amps on low speed - and can I do better?
You can measure current - Great!
You almost certainly need to (this will sound terribly counterintuitive, but you can use an ammeter and see it!) restrict the ductwork this is connected to. There might be a large master damper, or you might have only individual dampers, or perhaps you have to add dampers or put boards partly over registers.
You have already seen the current go up in &quot;free air&quot; - when you restrict the ductwork, you should see the current drop. When you have restricted it enough it will be drawing 10A on &quot;high&quot; - based on the information you have provided.
Bottom line - when it's driving the fan, it's doing work. When it moves more air, it does MORE work. When you restrict the airflow, it does LESS work and draws LESS current. People &quot;intuitively&quot; tend to think that restriction makes it &quot;work harder&quot; but that is not the case with a centrifugal fan. It's &quot;counter-intuitive.&quot;