I'm new to dynamo hubs and have a question regarding my recent buy. I bought this dynamo hub and wheel off ebay. When I rotate the wheel by holding with hand, I feel a clicky feel instead of a smooth turn/movement. I emailed to the seller and he recommended to put it on the fork to try it. I did that and it's bit less noticeable but still I can feel its clickiness especially when it's about to stop turning. I can feel in the frame too when it's spinning fast. I do expect some drags but I thought dynamo hubs are frictionless which means it turns freely and smooth.

Is my dynamo hub something wrong? Do all dynamo hubs do this or just mine does it? Is there frictionless dynamo hub?