Engineering
2 H-Max Series Adjustable Frequency Drive    MN04008005E—September 2011    
Electrical Power Network
Input Connection and Configuration
The H-Max series frequency inverters can be connected and 
operated with all control-point grounded AC power networks 
(see IEC 60364 for more information).
AC Power Networks with Grounded Center Point 
(TN-/TT Networks)
While planning the project, consider a symmetrical 
distribution to the three external conductors, if multiple 
frequency inverters with single-phase supplies are to be 
connected. The total current of all single-phase consumers is 
not to cause an overload of the neutral conductor 
(N-conductor).
The connection and operation of frequency inverters to 
asymmetrically grounded TN networks (phase-grounded 
Delta network “Grounded Delta”, USA) or non-grounded or 
high-resistance grounded (over 30 ohms) IT networks is only 
conditionally permissible.
If the H-Max frequency inverters are connected to an 
asymmetrically grounded network or to an IT network 
(non-grounded, insulated), the internal interference 
suppression filter must be disconnected (unscrew the screw 
marked EMC, see “Installation in IT System” on Page 33). 
The required filtering for electromagnetic compatibility (EMC) 
is then no longer present.
Measures for electromagnetic compatibility are mandatory in 
a drive system in order to meet the legal requirements for 
EMC and low voltage regulations.
Good grounding measures are a prerequisite for the effective 
insert of further measures such as shielding or filters. 
Without respective grounding measures, further steps are 
superfluous.
Input Voltage and Frequency
The standardized input voltages (IEC 60038, VDE017-1) for 
energy suppliers (EVU) guarantee the following conditions at 
the transition points:
●
Deviation from the rated value of voltage: maximum ±10%
●
Deviation in voltage phase balance: maximum ±3%
●
Deviation from rated value of the frequency: 
maximum ±4%
The broad tolerance band of the H-Max frequency inverter 
considers the rated value for
European as (EU: U
LN
 = 230V/400V, 50 Hz) and
American as (USA: U
LN
 = 240V/480V, 60 Hz) standard 
voltages:
●
230V, 50 Hz (EU) and 240V, 60 Hz (USA) at HMX32
●
400V, 50 Hz (EU) and 480V, 60 Hz (USA) at HMX34_
For the bottom voltage value, the permitted voltage drop of 
4% in the consumer circuits is also taken into account, 
therefore a total of U
LN
 –14%.
●
200V device class (HMX32):
208V –10% to 240V +10% (188V –0% to 264V +0%)
●
400V device class (HMX34):
380V –10% to 480V +10% (342V –0% to 528V +0%)
The permitted frequency range is 50/60 Hz (48 Hz –0% 
–66 Hz +0%).
L2
N
L1
L3
PE
L2
PEN
L1
L3