Is 40 days gap in 2 salary period necessary? please guide

As per POW Act section 5, within 7th of the next month if the no. of employees are less than 1000. And if the employees' strength is more than 1000 then 10th of the next month. Please check the applicability too as if I am not wrong at present the ceiling limit is Rs 24000/-.

As rightly pointed out by Adv. Pradipta Nath, you salary needs to be paid by 7th/ 10th of each month.