Originally posted by Double D:
I have just found out a theatre has been operating using two ESU's at the same time with no problems far a long time but a sales rep has advised they should'nt be operating like this.
Can any of you advise me if this is a safe working practice or not? They are using 2 return plates placed on the same limb and both working in the same area. Dave
There is a possibility that the frequencies of the 2 ESUs may differ by a small amout (50 Hz say) and may interfere with each other and produce a beat frequency of 50Hz that may be very dangerous to the heart (Physiotherapists call this Interferential Frequency therapy)
