Air compressor cannot restart when reaching low pressure setpoint

by Jacques Pagé
(Montreal QC Canada)

My Compressor (belt driven iron pump) starts OK when empty and runs until it reaches the set PSI value.

When I use the air and the pressure reaches the low point, it refuses to start again, tripping the breaker.

I thought it was the motor so I went to a shop to have it checked and they told me it was OK. Then I went to another place and they told me the pump is fine...What would be the problem?

Could it be some kind of back pressure in the pump, rendering the restart so hard as to overcome the motor's capacity on startup? If so, what causes it?

Thanks