For such drive & control type of equipment one cannot seriously define a "tolerance range" for the transient voltage spikes on your customer's mains supply. Such surge voltages are basically a threat to all electrical equipment in that factory and will cause more rapid ageing and sooner or later -or instantly- damage the equipment. Which is then of course not covered by any product warranty. So the question should not be, how much suffering the devices might be able to bear, but how to prevent and take control of such problems and thus keep up availability of the production equipment. Common practice would e.g. be to install transient surge protection devices (SPD), which are available as standard catalog products from all major manufacturers.
... View more
