force starting AC compresser

[EDWARD757]

Hi,
I have just ordered a new condenser and have heard that after regassing, a few members have needed to force start the compresser (by connecting 12v directly to it) to overcome the protection pressure switch and then the system will sense the gas and operate the compresser correctly. Where and which polarity does one connect to the compresser?
Any other top tips appreciated....
Kind regards,
Ed