One control and one fan frequency conversion speed control circuit a

Renault RNB3000 series frequency converter controls one
(that is, one frequency converter controls one motor) fan (or
water pump) frequency conversion speed control circuit as shown in Figure 5-11.
    In the figure, l and 2 are fault output terminals; 4, 5 and 6
are analog voltage input terminals; 6 and 8 are analog output
terminals; 19 and 20 are forward running terminals.
    Press the start button SBi, the fan
starts to run at the frequency set by the potentiometer RP.