help with IR2110 chips

[Maglatron]

I found the equation used before

2 x pi x 7 / 2.5. I thought you were using a different wheel from the one in the pic.

okay divide circumfrence by pi then half: 50 / 3.14 = diameter then half for 7.96cm radius thanks

 

[Alec_t]

It's actually a tad more than 50cm circumference, because the magnet diameter is a chord rather than an arc.

 

[Maglatron]

ok so taking that into consideration? I am considering a strait 8cm radius to the centre should be fine!!