Why my phone is switched off when updating to windows 10 mobile?

[KRHCKD93]

I am updating to windows 10 mobile and installation of the update was started but after some time my phone turned off. I waited for some time but nothing happened. When I try to switch it on it vibrates and the gears appear and after around 20 secs it switches off again.
Is that supposed to happen?
I am just hoping this is part of the installation process.

Please help.
Thank you.

 

[Harrie-S]

I am updating to windows 10 mobile and installation of the update was started but after some time my phone turned off. I waited for some time but nothing happened. When I try to switch it on it vibrates and the gears appear and after around 20 secs it switches off again.
Is that supposed to happen?
I am just hoping this is part of the installation process.

Please help.
Thank you.

No that's not part of the plan. Could it be that your battery is low so connect it to the power supply.

 

[KRHCKD93]

I tried to charge it but this time it keeps switching on and off..What to do?
Edit: I also installed the recovery tool and it is not detecting the phone.