Connection example – DC link group (60 A to 170 A devices)

This connection technique enables you to establish a DC link group for servo drives from the series AX5160 to AX5193

The following illustration shows a possible configuration example.

Key to picture:

NOTICE
	Drive system with UL approval! Before implementation a DC link group, please contact your UL approval body and discuss further necessary boundary conditions.

Dimensioning of the UL fuses F_DC1-F_DCn

The dimensioning of the fusesF_DC1 to F_DCn in the DC link is application-dependent. The motor and the load profile are incorporated directly into the calculation. Please consider this when dimensioning.

NOTICE
	Fuse holders with UL approval Note when using UL fuses that the necessary fuse holders also have to carry UL approval.

Mains choke

To ensure balancing of all servo drives, a common mains choke (L_o) must be provided. The rated current of the mains choke must be ≥ the rated current of the common mains fuse (F₀) of the drive system (see section "Mains fuse"). The short-circuit voltage U_k of the mains choke must be 2%

Dimensioning the mains fuse

The following section describes the dimensioning of the mains fuse to be used for individual devices and the use of mains fuses in the DC link group.

Series AX5160 to AX5193 (60 A to 170 A):
Individual device:

• The main fuse must be dimensioned such that it corresponds to the rated current of the servo drive multiplied by the correction factor 1.1. The value determined is rounded up to the next larger standard step (see section Electrical Data). If the size of the current (in your application) on the mains side is known, the mains fuse can also be dimensioned smaller in accordance.
• The cross-section of the mains supply cable must be dimensioned such that the permissible current load of the cable is ≥ the rated current of the selected mains fuse (see section Motors and Cables).

DC link group:

• The common main fuse (F₀) must be dimensioned such that it corresponds to the sum of all the rated currents of the servo drives multiplied by the correction factor 1.1. The value determined is rounded up to the next larger standard step (see section dimensioning example). If the size of the current (in your application) on the mains side is known, the mains fuse (F₀) can also be dimensioned smaller in accordance.
• The cross-section of the mains supply cable must be dimensioned such that the permissible current load of the cable is ≥ the rated current of the selected mains fuse.
• The cross-section of the mains supply cable and the mains fuses (F₁ to F_n) of the individual servo drives in the DC link group are to be selected analogously to the operation of the individual servo drives (see section "Individual devices").

The local regulations and the local conditions (ambient temperature, cable routing, etc.) must be referred to when determining the permissible current load of the cables (selection of the necessary cross-section – see section Motors and Cables).

Dimensioning example:

Mains switch-on conditions:

The mains must be switched through to all servo drives simultaneously. Therefore, use a common mains contactor (K₀) for all servo drives. The phase error detection (grid monitoring) of the servo drives must be active. Observe the relevant parameterization for this (P-0-0204 Disable U_main monitoring and U_main phase error detection).

Parameterization P-0-0204:

The default values of the parameter P-0-0204 (Power management control word) are set to:

• Disable U_main monitoring = 0 and
• U_main phase error detection = 1.

In the DC link group the default values of the parameter P-0-0204 are to be checked before commissioning and set to the above values if discrepancies are found.

Parameterization P-0-0214:

To parameterize an AX5160 to AX5193 DC link group, the following settings must be made in parameter P-0-0214 (DC link connection mode):

• The value 0x000A sets the servo drives AX5160 to AX5193 to stand-alone mode
• The value 0x000B sets the servo drives AX5160 to AX5193 to DC link group mode

The external brake resistor is activated in both cases.

Mains filter:

If mains filters are used, a separate mains filter must be used for each servo drive. The mains filter must be positioned as close to the servo drive as possible. Use short cables without loops.

A suitable shield connection is ensured by adhering to the following points:

• The mounting plate must not be painted. The shield is automatically connected via the mounting plate.
• If the mounting plate is painted, the shield must be connected via the underside of the servo drive (earthing bolt).

Max. cable sizes accepted by the connecting terminals:

The maximum cable cross-sections are dictated by the maximum cable sizes that can be accepted by the connecting terminals on the servo drive (see table below):

Dimensioning of the brake resistors for operation in the DC link group:

In individual braking situations the energy balance in the DC link group can be generative. Servo drives from the series AX5160 to AX5193 have no internal brake resistor. External brake resistors must be used to dissipate the energy generated. The brake resistor must always be connected to the connector provided on the servo drive.

Under the following conditions it is possible to dispense with one or more brake resistors:

• the remaining brake resistors must be able to handle the continuous power
• the remaining brake resistors must be able to handle the short-term power
• the ohmic value of the brake resistor for each servo drive must not be lower than the minimum permissible value.

Part of the brake energy is also stored in the DC link, independent of the brake resistor. The more servo drives there are in the DC link group, the larger the storage capacity. It is therefore possible to store more energy.

The following must be considered when dimensioning the brake resistors:

• The external brake resistor must have an ohmic value that is at least as large as the minimum value permitted by the servo drive.

• The peak braking power of the DC link group is given by the sum of the peak braking powers of all the brake resistors in the DC link group:
  



• The continuous braking power is derived from the calculation of the effective braking power:

where:

DC link group with other AX5000 servo drives:

No DC link group permissible with devices for 1.5 A to 40 A! Servo drives from the series AX5101 to AX5140 are excluded from the DC link group with servo drives from the series AX5160 to AX5193 and may NOT be connected to one another! The DC link group described here is permissible only for AX5160 to AX5193 servo drives!