Will they send the police if I call the suicide hotline?

They will depending on how severe you report the situation to be. There is a huge difference between suicidal ideations and suicidal intentions. If you make it clear you are just thinking about it and you aren't actually in imminent danger (the difference between thinking of doing something versus having put yourself in a position to actually do it, like thinking of jumping from a building versus actually standing on the ledge) they won't send anyone. But if you're thinking of suicide, you should call the hotline regardless-you're life is more important than any possible consequence calling would have.

There are there to listen to you and try to understand where your comming from and to try and give you a reason not to d anything,but! it it seems to them that you are about to end it, they will call the police.
They have a duty of care to do so.

I've never heard of one that does, but then I'm not experienced with suicide hotlines. I'm pretty sure there are either too many callers or too few actual suicide cases for that to be a viable strategy, considering that the police is a fairly limited resource. I wouldn't worry about it.