Voltage and frequency considerations for AC powered Rainman watermaker

Rainman AC systems come in either 230VAC / 50Hz or 115VAC / 60Hz. This covers the vast majority of AC power set ups around the world (the Philippines is an exception). These systems are almost identical, except for two factors. The AC induction motors are manufactured for either 230VAC or 115VAC. Also, the shafts on the high pressure pumps have different throw lengths, optimising the system for either 50Hz or 60Hz operation.

If you run a Rainman 230VAC / 50Hz system at 60Hz, the motor will spin 20% faster. This means the pump is moving 20% more water, the AC motor is doing 20% more physical work, and is drawing a higher current. This will eventually overheat the motor and lead to motor failure.

If you run a Rainman 115VAC / 60Hz system at 50 Hz, the motor will spin 17% slower. This means the pump is moving 17% less water, the AC motor is doing 17% less physical work, and is drawing a lower current. This lower flow rate will slightly decrease the product water output and slightly increase the total dissolved solids of the product water, but will not harm the system.

Conclusion

You should ensure you know what power (voltage and frequency) you have available when ordering a Rainman AC watermaker.