Runs too fast with the rotor?

[Leslie 62]

I have an automatic watch that runs at about +2 sec/hr on average (not steadily in each hour, ranging from +0 to +4 sec/hr in a day)
Then, I took the rotor (oscillating weight for auto winding) off, and now it runs about +0.3 sec/hr steadily.
Anyone has similar experience? How do I explain this?  Thanks in advance.

It is a cheap replica Panerai (a PAM392 copy? See pictures).  I have the other automatic watch (I forgot which one) that also behaves like this -- runs unexpected fast during some period, but runs stably fine without the rotor/automatic unit. 

 

[GenTLe 1,501]

The rotor recharge the main spring, so the amount of force transmitted to the balance wheel is not constant like without it. That's the reason.

But mate... Once you regulate it on average day, it will be fine. It's an auto: COSC certification means to have it between -4/+6 secs a day! Not at hour...

[NCRich 13,748]

I read the title and thought "dances with wolves"

[Nikosaldente 630]

5 minutes ago, NCRich said:

I read the title and thought "dances with wolves"

Tatanka

 

[Leslie 62]

12 hours ago, GenTLe said:

The rotor recharge the main spring, so the amount of force transmitted to the balance wheel is not constant like without it. That's the reason.

But mate... Once you regulate it on average day, it will be fine. It's an auto: COSC certification means to have it between -4/+6 secs a day! Not at hour...

That is a very reasonable explanation. Thanks! 

 

12 hours ago, NCRich said:

I read the title and thought "dances with wolves"

Thanks for the reaction. I don't know how to reply.  Give you my favorite Emoticon:   

[Leslie 62]

I found the similar problem (for my ST2555 movement) here:

Seagull 2555 Movement runs fast ONLY when rotor wound

(i.e., http://forums.watchuseek.com/f72/seagull-2555-movement-runs-fast-only-when-rotor-wound-954226.html )

I am not sure if such a link copy is legal or not?