Emerson 400518-01 - Manual (Page 26)

14
Safety Information Product Overview Installation Diagnostics
Options and
Accessories
Specification
Figure 12: Grounded WYE Distribution >140 Vac Phase to Neutral. Recommend Using
Step Down Transformer so Line to Line is 240 Vac or less.
Figure 13: Single Phase Power Supply Connections
Transformer Sizing
If your application requires a transformer, use the following table for sizing the KVA rating. The values in the table
are based on “worst case” power usage and can be considered a conservative recommendation. You can down-size
the values only if the maximum power usage is less than the transformer continuous power rating. Other factors that
may influence the required KVA rating are high transformer ambient temperatures (>40° C or >104° F) and drive
operation near the maximum speeds.
Transformer output voltage drop may become a limiting factor at motor speeds and loads near maximum ratings.
Typically, higher KVA transformers have lower voltage drop due to lower impedance.
DISTRIBUTION PANEL 3 Ø Isolation Step Down Transformer
EARTH
GROUND
(Protective Earth)
N
L1
L2
> 140 Vac
L3
PE
To Fusing and
Drive Terminals
Fuse
L1
L2
To Drive
Terminals
Fuse
Fuse
L1
L2
To Drive
Terminals