Cooling circuit in the application

When water-cooled motors of the SIMOTICS FD series (1LH1, 1LN1) are operated in the application, they become part of the overall cooling circuit. Apart from the cooling unit, this can include other heat sources.

The construction of the cooling materials demands two completely different cooling concepts for the overall cooling circuit in the application.

For the coolant circuit in SIMOTICS FD motors of the 1LH1 and 1LN1 series, the materials listed in the table "Materials used in the motor (cooling circuit)" can be deployed which provides the user with a range of possibilities for constructing the cooling circuit.

The electrochemical processes that take place in a cooling system must be minimized by choosing the right materials. For this reason, mixed installations, i.e. a combination of different materials, such as copper, brass, iron, zinc, or halogenated plastic (PVC hoses and seals), should not be used or should be limited to the absolutely essential minimum.

Please read the following definitions for clarification:

1. Closed cooling circuit:
The pressure compensator is closed (no ingress of oxygen) and fitted with a pressure-relief valve (6 bar for 1LN1 motors, 3 bar for 1LH1 motors); it is always connected on the suction side of the pump. The coolant is only routed through the SIMOTICS FD motors, the components required for cooling and, if necessary, a converter. The materials used in the cooling circuit comply with the recommendations in the table "Admissible materials for the overall cooling circuit".

2. Semi-open cooling circuit:
Oxygen can only enter the coolant through the pressure compensator, otherwise the cooling circuit corresponds to a closed cooling circuit.

3. Open cooling circuit:
The coolant is guided through the motors and the cooling components required for heat dissipation as well as through components external to the cooling circuit. The materials used comply with the minimum requirements specified in the table "Admissible materials for the overall cooling circuit".

Possible cooling circuits of the SIMOTICS FD motor series

For further information on the construction of a cooling circuit, see the Manual "SINAMICS S120 – Chassis Liquid Cooled Power Units".

Cooling water quality

The water-cooled versions of the SIMOTICS FD series offer solutions for different qualities of cooling water. The optimum cooling water quality can therefore be selected in accordance with the location and application. The following tables contain the water properties defined for the various motor versions.

Definition of water properties

Assignment of motor versions to cooling water quality

Materials used in the motor cooling circuit

Motors of the 1LH1 series are equipped with built-in cooling pipes constructed from copper as standard, or as an option from stainless steel (order code M85).

Motors of the 1LN1 series are equipped with a double-walledair-to-water heat exchanger. The materials used in the 1LH1 and1LN1 series are listed in the table below.

Materials used in the motor (cooling circuit)

Admissible materials for the overall cooling circuit

? Admissible
– Inadmissible

Inhibitors, anti-freeze, biocides

Coolant additives

¹⁾ Effectiveness regarding the growth of microorganisms.