A formwork vibrator works with precast concrete. You attach form vibrators to the outside of your concrete form so it can vibrate the air bubbles out. Surface vibrators, or jumpers, go directly onto the top of your poured concrete.
Frequency convertors are the safe way to use high frequency vibrators and they reduce incoming 3 phase or single phase power at the vibrator head to 42V/200HZ.
Beton Trowel BTHFC60/12 High-Frequency Concrete Vibrator (Electric)