TECO F510 series - Input Power and Cable Length

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3.3.8 Input Power and Cable Length
 Cable size
The length of the cables between the input power source and /or the motor and inverter can
cause a significant phase to phase voltage reduction due to the voltage drop across the cables. The
wire size shown in Tables 3.3.6.3 & 3.3.6.4 is based on a maximum voltage drop of 2%. If this value
is exceeded, a wire size having larger diameter may be needed. To calculate phase tot phase voltage
drop, apply the following formula:
Phase-to-phase voltage drop (V) = 3 ×resistance of wire (Ω/km) × length of line m) × current×10
-3
.
(km=3280 x feet)
(m=3.28 x feet)
 Cable length vs. Carrier frequency
The allowable setting of the PWM carrier frequency is also determined by motor cable length
and is specified in the following Table 3.3.8.1.
Table 3.3.8.1 Cable Length vs. Carrier Frequency
Cable length between
the inverter and
Motor in m (ft.).
< 30
(100)
30 – 50
(100 – 165)
50 – 100
(166 - 328)
> 100
(329)
Recommended carrier
frequency allowed
Parameter 11-01
16kHz
(max)
10 kHz
(max)
5 kHz
(max)
2 kHz
(max)
 Installing an AC line reactor
If the inverter is connected to a large-capacity power source (600kVA or more), install an
optional AC reactor on the input side of the inverter. This also improves the power factor on the
power supply side.