Belt drive system with automatic belt tension control

A method of preventing a belt slip comprising the steps of:

• operating a drive having a belt engaged with a first accessory and a second accessory, said belt having a tension;
• measuring a first accessory hubload, a second accessory hubload and a second accessory rotational speed;
• calculating a first accessory slack side tension using a first accessory hubload, a second accessory hubload and a second accessory rotational speed;
• detecting a first accessory load condition;
• calculating a first accessory belt slack side tension using a first accessory load condition;
• comparing a calculated first accessory belt slack aide tension using a first accessory load condition to a calculated first accessory belt slack aide tension using a first accessory hubload, a second accessory hubload and a second accessory rotational speed;
• and
• adjusting a belt tension by a pivotal movement of the first accessory.

A system for controlling an endless drive member tension comprising:

• an endless drive member having a drive member tension manifest at an idler pulley as (FIdr);
• a first sensor detecting (FIdr) and generating a first sensor signal;
• an alternator connected to a frame, the frame having a pivotal engagement on a mounting surface, the alternator engaged with the drive member;
• a moveable member engaged with the frame;
• a second sensor detecting a position of the moveable member;
• a module receiving the first sensor signal and second sensor signal, the module generating a control signal wherein T tm = F Idr 2 ⁢ Sin ⁢ ⁢ ( θ Idr 2 ) ⁢ ⁢ and T sm = H Alt ⁢ L 1 + L 2 L 1 Sin ⁢ ⁢ ( θ Alt 2 ) - T tm , ⁢ and T Alt = R Alt ⁡ ( T tm - T sm )
• where
• Tsm=Alt slack side tension calculated from measured data
• Ttm=Alt tight side tension calculated from measure data
• FIdr=Force measured at the idler
• HAlt=Alternator hubload
• L1=Distance from pivot to Alt pulley center
• L2=Distance from Alt pulley center to load cell
• θIdr=Idler pulley wrap
• θAlt=Alternator pulley wrap
• RAlt=Pitch diameter of alternator pulley
• TAlt=Alternator torque
• where “Alt” refers to an alternator;
• and
• the moveable member responsive to the control signal, whereby a moveable member movement adjusts an alternator hubload (HAlt) and thereby (FIdr) by pivotal movement of the frame.