DE1936726C - Cooling unit for containers - Google Patents

Description

4P The invention relates to a cooling unit for a container, with electric motors connected to networks with voltages of two classes by simply switching over the electrical connections of the windings of the motors are connectable, with a device that can be connected to the networks that between differentiates between the two mains voltage classes and through which the electrical connections of the The motor windings can be switched to match the nominal voltage of the motors to the mains voltage of the The network to which the cooling unit is connected.

The term container is understood here to mean a closed and thermally insulated container with a Cooling unit is or can be equipped, for example, a compressor, a condenser, a Throttle body and a cooler as well as electric motors and heaters to perishable goods that are transported by a truck or ship.

6p Such a container is often used between different Countries by land and sea or periodically transported back and forth between two places. The problem arises that the mains voltage of the Stromversorgungsnetee is not everywhere is equal to. The mains voltage is for the individual countries, areas within a country, ships, Railways and even different for different companies. The mains voltages can

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basically divided into two classes, connected in class, but not switched to whom

the 200 V class and the 400 V class. The over- the cooling unit to a network of the lower, span

Borrowed containers are basically connected for a voltage class, and finally, eir

power class. This makes the use slow switching for every line voltage class!

connection of cooled containers to different 5 relays, the higher voltage with the secondary connection

Oiten very difficult. In some cases it is the transformer connected, with dif

half necessary, a special power source to be interlocked in both relays,

enamel to power the refrigerated container

to supply. position the cooling unit on the one that has just been applied «

It is the object of the invention to automatically supply the mains voltage to the mains so that the Be

The cooling unit that can be connected to two classes of voltages is only used to connect the cooling unit to the network

for a container to be designed in such a way that a more secure one needs to close without the need for a first switch

Operation is guaranteed in the sense that the engine handle according to the invention as in the first-mentioned

Windings must in any case be operated against harmful network solution.

voltages are protected. i $ It is already an automatic switching device

This object is achieved on the one hand that for electrical heating devices with different the device has two specially designed networks that feed voltages and types of current plug that does not plug into the socket of the respective an- especially for track vehicles, has become known whose power plug fit that each power plug (see. German Patent 733 160), the Umeine its own first switch unit is connected downstream, 20 switching between alternating current (in particular that the two switch units against each other 1000 V) and direct current (in particular 1500 unc are locked and. that second switch units to 3000 V) takes place. This known in the coil circuit Switching of the motor windings are provided, th switching device are electric valves of the which are arranged with the first switch units in a group that they block with direct current penschalter are summarized. 25 act, with alternating current switching processes

So if the first and second trigger accidentally and immediately after the switch has responded, Switch units that cannot be bridged in the straight direction. Furthermore, this order can inserted mains plug are connected downstream, switching device has to be designed so that when be this only has the consequence that the motor windings are not correct operating voltages a part of a valve get excited. This is noticed by the operator, who loses its locking effect and switches off. then causes the currently plugged-in network gears while the group is in their plug-in downstream first and second switch assembly avoids undesired switching operations unit is actuated, via which the motor windings are then operated be excited. Connection of the heating device to an alternating current

An advantageous further development of the invention consists of voltage and a direct current voltage or ar is that the group switch has an additional alternating current voltage and two direct current pairs of switches which are provided with one or two relays in the control circuit voltages,
Electromagnetic contactors are switched on. In addition, a multi-voltage heating system is connected in order to control a connection that no longer requires the nominal tronic control (cf. magazine voltage of the contactors to the network 40 »Electric Railways«, Volume 32 [1961]) , H. 10 voltage adjusts, with main contacts of the switching p. 227 to 235), through the electrical Zugheizungsschützen between the first and second switch devices under the same power consumption mi units are provided, and that the additional pair of operating voltages of 1000, 1500 and 3000 V be are to be driven by switches in the group switch in such a way that the heating elements are set in such a way that the switches of this additional pair 45 are subdivided so that they are opened depending on the existing load before the switches are opened according to the supply voltage The associated first and second switch units can be grouped and, in each case, one of the same size The heating power will be closed after it has been closed. submit. Thereby relays, changeover contactors

By using electromagnetic switching electron tubes or transistors and diodes (ir

contactors prevent the switches from being switched on when connected

let and stop the high voltage motors finally a stabilized power supply for

switch. the controlling components used, so that dei

Another solution according to the invention, the up-effort is considerable.

There would be that the device is electromag- The invention is also embodied in this way Magnetic contactors for switching the motor 55 tet that the motor windings have three phase windings

windings a tension sensing device, which have with that by the second switch unit

Mains lines of the cooling unit is connected, and / or the contactors for switching the motor

has several relays, which the excitation coils of the windings between star and delta connection

second electromagnetic contactors' are correspondingly switchable, and that the motor windings dre corresponding to the detection of the voltage through the span 60 phase windings, and that the phases

excite the voltage sensing device, and that the voltage windings each have two identical partial windings

sensing device comprises a transformer that has to be connected between series and parallel connection ir

Power lines of the cooling unit is connected and each phase through the second switch units or

two sizes of secondary voltages generated, fer- the contactors for switching the motor wind ner a fast-switching relay that can be switched over with the 65 settings.

Kundäranschluss lower voltage of the Transfor- Finally, the fm

mators is connected and switches quickly if the proper cooling unit or overload sensor it

Have the cooling unit connected to a network of the higher line voltage series with the motor phase windings.

The invention is based on the drawing in more detail while an additional winding (u ₂ rv _? ) In series with

explained. It shows the above parallel connection is for one

Fig. 1 is a circuit diagram of an embodiment of operation at 200 V, the circuit should be made as in Fig. 8b according to the invention, in which the switching of the electrical, whereby the additional winding fresh connections by hand switches gave birth in parallel to the above-mentioned parallel connection is switched is. An electromagnetic contactor MS ₁

Fig. 2 is a circuit diagram of an embodiment controls the compressor _{motor M 1} and the condenser

a simpler cooling unit according to the invention, satormotoreri M ₂ and M ₃ , while an elektröma-

in which the manual switch is in a compact cam- netic contactor MS _{2 and} the _{fan motors M 4}

kenschalter can be combined, io and M ₅ controls the cooler. Furthermore, a water

Fig. 3 is a diagram from which the switching sequence switch WS available. The cooling unit also has

of the cam switch can be seen, which has a heater A ₁ for defrosting the cooling hose

example of FIG. 2 can be used gen and for heating air, a second

F i g. 4 the circuit diagram of an automatically working heater A ₂ for the drain pan and a third

the embodiment according to the invention, 15 heater A ₃ for a drain pipe. The three heaters A ₁ , A ₂

F i g. 5 a and 5 b circuit diagrams of the windings of a and A ₃ are both on a 200 V and on a double three-phase induction motor. 400 V mains can be connected. An electromagnetic contactor MS ₃ controls the heater for the cooling unit according to the invention,
can be seen, where F i g. 5 a the arrangement for a group switch SS such as a multi-line voltage of the 400 V class and F i g. 5 b for ao multi-step cam switch or a rotary switch pre-represents and handle a line voltage of the 200 V class, which can be operated by hand. The one from one

6a and 6b circuit diagrams of the windings dashed-dotted switches in the drawing of a double designed single-phase induction mo- tion all belong to the group switch SS, from the gate which is used for the cooling unit according to the invention switching contacts // closed during 400 V operation , where F i g. 6 a are the arrangement for »5, while switching contacts L are closed in the case of 200 V operation, a line voltage of the 400 V class, and FIG. 6 b. A coupling device is shown in front for a mains voltage of the 200 V class, through which at least one // contact and

For the in F i g. 1, 2 and 4 motors shown, an L contact must be closed at the same time. A

it is assumed that they have the functions shown in FIG. 7 a and 7 b transformer Tr supplies a control circuit with

have the circuit shown. Furthermore, in FIG. 4 30 electricity. The secondary winding of the transformer Tr

Single-phase motors and heaters for clarity are provided with a center tap. When connected

not shown because of. The switch contact L is closed on a 200 V NeJz for the same reason.

are also shown in FIG. 2 heater had been omitted. sen to one of the output terminals T ₀ and S _{0 of} the

In all figures, the entire circuit diagram of the transformer with one end of the secondary winding cooling unit is divided into three sections, ie to be connected in 35 ment. When connected to a 400 V network, an input section A, a consumer outlet, the center tap is connected to one of the output sections B and a control section C, R, S, T via the switch contact H. There are network connections, where A ₁ , S ₁ , T ₁ connections have the same voltage for all network voltages for a connection to a network of the 200 V class voltage of 24 V at the output connections T ₀ and and R ₂ , S ₂ , T ₂ for a connection to a network of 40 S ₀ , to which mean the control circuit of the electromagnetic 400 V class. table contactors is connected

In FIG. 1, plugs _{P 1} and P _{2 are shown} with the inputs. The operation of the above-described connections /? ,, S ₁ , T ₁ or A ₂ , S ₂ , T _{2 will} now be explained via the given control circuit. If appropriate cables are connected. The plugs P ₁ and P _{2 are} assumed that a 400 V network is available, are different shapes to avoid a faulty connection 45 the input connections J? ₂ , S ₂ , T _t with the new to avoid digestion. This means that the plug P ₁ can be tied, or the mains plug P ₂ is plugged into a suitable only 200 V socket and the plug P ₂ only plugged into the socket after the group switch has been plugged into a 400 V socket. In SS , the // contacts to Fi g. 1 also shows a circuit breaker CB . close, after which the circuit breaker CB is closed-the cooling unit has a compressor, iron cone 50 and then the electromagnetic capacitor, a throttle element and a cooler, the contactors MS ₁ , MS _v MS ₃ via a (not shown) one per se form known cooling circuit; more precisely corresponding control device closed what is said, as electrical consumers are present: a den. A 400 V mains voltage is therefore applied to the compressor _{motor M 1} , fan motors M ₂ and M ₃ consumers, all of which have been prepared for operation for the capacitor and _{fan motors M 4} and M _{5 55 40V.} In this case we are for the cooler. The compressor motor M ₁ is a double voltage, if the group switch SS is erroneously rotated, voltage-3-phase indicator, the order of which is around the L contacts, the tangles are connected in a delta circuit. Connections in the consumers on a nominal spring branch of the triangle consists of two Wkklun voltage changed from 200 V, whereby none of the elekgen that are in series for a 400 V network, as in Fig. 7a 60 Irish facilities will be damaged because the is shown, or in parallel for a 200 V power switch 400 V input voltage by the Gnippeaschal-If, as depicted in Figure 7b lterSS the fan itself (// - contacts in section a) also motors M _2, M ₃ , M ₄ and M ₅ are single-phase inductive disconnected

fion engines. When operating with 4tS0V, the If it is now assumed that a 200 V network

"Windings of the single-phase motor as shown in Fig. 8a is available, the input connections S ₁ , S ₁ ,

be formed switched. That means, Üe Hanptwick- T ₁ or the mains plug P _{1 connected} to the mains,

OuTIg (H ₁ -V ₁₎ is parallel to the series sheep Tung m of which the group switch SS rotated so vw ^ l that

* imd a capacitor switched, it closes the L-contacts Then throw the Ld-

circuit breaker CB and the electromagnetic supply of 400 V are switched. The cam contactors MS ₁ , MS _S , MS ₃ in the same way switch SS is closed with locking recesses in the as before. In this way, the positions of the notches No. 1 and 4 provided, a cooling unit begins to work, whereby 200 V mains voltage such locking device is not applied to the loads, which this 5 in the other positions, namely the notch No. 2 voltage have been adjusted. . Faiss the group-and 3 and vorpenschalter in the rest position of the notch N ° east SS should have been erroneously operated, seen: the contacts of the switch SS are so close angeum the fJ contacts occurs assigns no over- that when turning the switch SS by a utilization because the mains voltage has also been turned off by the same lever from the notch no. 1 in the notch no. 4 through group switch SS io the notches Nos. 2, 0 and no. 3 of the contact L ₈ unjst. is opened indirectly after the switch lever the

By using the plugs P ₁ and P ₂ with con-notch no. 1 has left, while the other contact pieces, which are designed differently from one another, are only opened after the lever detects the notch and therefore only plugs into the correct socket No. 2 has passed. Furthermore, the conbars are, a damage or malfunction is intact H until H ₃ in the position of the notch no. 3 resulted in a faulty connection to the mains or a closed, while the contact H ₄ only closed incorrect actuation of the switch absolutely disappears after the lever reaches notch no. 4. avoided. Similarly, if the operation is reversed

A different embodiment is now intended to _{open only the contact / Z 4} when the lever measures the dimensions of the invention with reference to FIG. 2 and 3 be ao notch no. 4 leaves, and the other contacts H ₁ are written. The in F i g. Control to H ₃ shown in Fig. 2 will be opened after the notch No. 3 facility is essentially the same as that in Fig. 3 is passed through. Furthermore, the contacts L ₁ to L ₅ F i g. 1 shown, with the exception of closed in the position of the notch no. 2, while the single-phase motor and the heater in FIG. 2 the contact L _{6 is} only closed after the have been omitted, the description of the working lever of the notch no. 1 has been reached. It can be seen from the group switch on the basis of FIG. 3 to Hch that the switch SS is so constructed that the simplify. A transformer Tr ₁ for Stromein- lever does not feed directly from the notch no. 1 into the notch in the control circuit of the electromagnetic no. 4, so without going through the notches no. 2, 0, see contactors MS ₁ , MS ₂ has a Center number 3, and vice versa, can be turned, tapping on the primary winding. With 400 V operation 30 Due to the structure of the Noks described above, the power supply lines at both ends of the switch SS will be connected to the operational reliability of the primary winding, while ensuring the choice of the mains voltage. Furthermore, 200-V operation, the power supply lines to which the current interruptibility of the contacts of the Nok center tap and one end of the primary winding kenschalters can be greatly reduced, so that the should be connected, so that a constant Se- 35 switch can be built smaller and one Longer secondary voltage of 24 V between the connections shows service life. When the lever of the cam A ₀ and S _{0 is} maintained. It can be seen that the switch during operation of the cooling unit means that this double voltage requirement is turned on, the contact H ₄ (or L ₆ ) is opened before the secondary side of the transformer is opened, as in the first of the other contacts H ₁ to H ₃ (or L ₁ to L ₆ ) guide example can be made. 40 opens, and thereby the electromagnetic

Switch contacts L ₁ to L ₆ and H ₁ to H ₄ belong to contactors MS _v MS ₂ , which for the correct control to a single cam switch. The order provided for contact to the corresponding consumer currents is shown in FIG. 3 pictured. In Fig. 2 and 3 are and are _{excited by the transformer Tr 1} , in front of the contacts L ₁ and H ₁ can be seen in order to connect to a 200 V between the opening of the contacts H ₁ to H ₃ (or L ₁ to L ₆₎ - and a 400-V-Net / 45 opened. In addition, the must be selected when commissioning; Furthermore, the contacts L ₂ , L ₈ and H ₂ to the cooling unit, the contacts H ₁ to H ₃ (or L ₁ to L ₅ ) change the connection of the windings of the grain - always before the electromagnetic pressor motor M _{1 is closed} , the contacts L ₄ , L ₅ and H ₃ to the contactors closed. Therefore, the Kon change of the connection of the windings of a single-ended cam switch SS is reliably protected from strong phase motor M ₈ and contacts L ₈ and H ₄ for 50 currents during the start-up and shutdown phase selection of the primary-side connection for transit operation It should also be built on door ₁ . be pointed out that when the

If a 200 V power supply is available, the cam cooling unit is common to the electromagnetic kenschalter SS in the position of the notch no. 1 part by SChBItSCbUtZeMS ₁₁ MS ₂ manually by a pressure rotating after the power plug P ₁ in a matching 55 button or to switch automatically after the mains socket has been plugged in. In this way, the cam switch SS in the notch no. Ϊ or 4, the contacts L ₁ to L _{6 are} closed and the has been. Furthermore, it should be pointed out that contacts H ₁ to H _{4 are} open so that the mains voltage can be remotely controlled so that the cam switch SS is applied to the consumer by a control motor built there by 200 V. Initially connected for the same voltage. If this embodiment has a voltage of 400 V that is already available in this embodiment - is not described for the previous embodiment, the cam switch SS in notch no. 4 will have the following advantages.

"iasturns after the Netestecker P ₂ in a 400-V- Em another embodiment according to the

has been put sfetzsteckdose This time advertising-making should now aa reference to FIG. 4 described

L the contacts B ₁ Ms M _{4 are} closed and the Eon-63 are. Bd this third Ausfütaingsbeispiel is

"e L, to L ₈ open, so that the mains voltage the switching"} of the connection auti under Ver-400 V to the motors M ^ and M ₂ as well as the turning of the electromagnetic shadow hats, which are coupled to the operation ODtetemander

_{2 is} created, all for the

10

are. A transformer Tr that does not feed a control current through a low voltage such as 12 V

Carries out supply is driven with a center tap. Therefore, only the relay MR _{2 is} actuated, and

b., provided on the secondary winding. The Umspann- the coil MC _{L of} the contactor is energized to

ratio of the transformer is chosen so that when the contacts MS _L to close, while the coil

Applying 400 V to the primary winding 48 V 5 MC _{H is} prevented from being excited, so that the

between the two ends b _x and c of the secondary winding contacts MS ,, are kept open, namely in

ment occur while 24V between the end c in a manner that is similar to that described above.

and the center tap O ₂ occur. Between this, the motor M _{1 is used} to operate

A fast switching auxiliary 200 V is prepared for connections b ₂ and c, and it runs safely after closing

relay MR ₁ switched, which is designed for 24 V. An OK of the contactor MS ₁ .

Another auxiliary relay MR ₂ , which switches slowly, as already mentioned, there is an automatic one between the connections b _x and r. The switching of the connections in the loads entRelais MR ₂ is also designed for 24 V, can be enabled depending on the class of the mains voltage, but can be operated at 48 V for a short time. Switch - by using a combination of two relays MS _n are working contacts of an electro- 15 which have different working characteristics magnetic contactor, which has a coil MC ₁₁ .

has, and switch contacts MS _L are through a The above-described embodiments

Coil MC _L actuated. On the other hand, normally closed contacts have overload sensors OC, which are placed between the winding

MS ₁₁ , and MS _L ,, ie normally closed gene of the compressor motor M ₁ in a special way

Contacts assigned to the coils MC _n and MC , ao are connected. The usual arrangement of over-

Furthermore, contacts Wr ₁ and mr., Normally load sensors for a motor with two classes

open contacts of the relays MR ₁ or MR., and Kon- can be operated by mains voltages, exists

clocks / W ₁ , and mr. ,, normally closed contact in switching of two sets of such sensors with

clocks of the relay. different rated currents, each with

The operation of this embodiment is now to be carried out with one set for each mains voltage, in series with one

game. If adopted, motor switch or circuit breaker in two or more

that the input connections R, S, Γ to a three-phase all power lines. Has such an arrangement

400 V mains are connected and the power but the disadvantage that the manufacturing costs for

switch CB is closed, the voltage of the overload sensors as well as that of them is

400 V applied to the transformer Tr , so that a space required in the control housing can be doubled.

Voltage of 48 V between the terminals b _x Further is a means for selecting a set

and c and of 24 V between the connections b., of the two sets of sensors according to the mains

and c occurs. Therefore a voltage of 24 V is required.

at the relay MR _x and 48 V at the relay MR _S. These difficulties are created by the invention. Although both relays work at the same time, it was overcome. In the training according to the invention, the relay MR _{1 works} faster than that is a single set of overload sensors as well as others. It should be remembered that the relay operative _x around the motor during operation so-MR a fast-switching relay, while the well-to protect at 200 and at 400 V. The relay MR _{t is} a slowly switching relay. Therefore, like overload sensors are known per se, for. B. the normally closed contact 40 interrupts various types of combinations of Heizfüh- mr _x . the relay MR ^ learn the power supply to the relay and temperature-dependent bimetallic sensors or MR _t before this experience a greater movement electromagnetic coils with immersion cores. A has. Therefore, only the relay MR is actuated _1, currency such sensor actuated upon occurrence of an end the relay MR ₂ remains energized Accordingly, load a normally closed contact in the spool MC _n of the electromagnetic switch 45 to a control circuit of the electromagnetic contactor via the two normally open contactor to thereby open the contactor and clock mr _x and shut down the two normally closed motors.

nen contacts mr _v energized to the contacts MS ₁₁ to In Fig. 5a and 5b denote the reference numerals

close and Jen contact MS “. to open, the one in R, S, T mains connections: IZ ₁ , U ₂ , V _x , V _% , W _x . W _s ,

Series with the coil MC _{L is} connected. In the middle 50 X _x , Y, Z ₁ connections of the partial windings of the motor

Time is the idle state of the electromagnetic M ₁ of FIG. 1, 2 and 4 and d, e, f, d _v e _v f _lt d "e _r

see SchaltschQtzesAfCt through the two normal / "conductors between the windings. With the 400 V

wise closed contacts mr, the relay MR _x operation of the motor M ₁ , as in Fig. 5a abildei

and the normally closed contact MS ". the overload sensors are located in the conductors d

of the SchaÖscbützes MC " guaranteed, so that the 55 e, f or in two of the three conductors, mn unite

Ksat ^ kleacSi stay open. This way, there will be overload current in the windings when it is on

determine the compressor motor M ₁ to operate at 400 V. On the other hand, the 200-V

prepared, and after closing the electromagnet! - Operation when the windings according to Fig. Sb ge

Let the switching signal MS ₁ run, the motor M _{1 is} safely switched, the same sensors with the same]

on. 60 nominal current in the conductors d _% (or <Q e, (or e.1

If the mains voltage is 200 V, this is / _t (or Z ₂ ) or in the other two of the three lei Voltage to the transformer Tt by closing it to protect the meter from overload

of Lunage CB created. In seconds. A comparison of the two operating modes: '

därwiddtmg of the transformer, 24 or 12 V enter the current consumption of the motor

iussenft. andc or. 6 _{s and} purchase. φ where the S & om for 200 V operation

• «ends 12 V at the ReIaIsMR ₁ tmil 24 V at §) elt as big as bete 40Q-V-Bfcf ¥ ieb fet De adelest JDa idaS relay iWÄj for doith each of the secte feBwickUmgen ffleßeade Strot —— of 24 V designed fet , however, is the same in both FSflen, as attached

11 12

200 V operation the phase current (ie the current between series with the partial windings, as described above, see the power lines), which is twice as large as connected, the sensing device is the same effective that is in 400 V operation between the Partly important to protect the motor both with the 200 V lung according to Fig. 5a and 5b is divided. Therefore, as well as with 400 V operation, since the normal current, the overload sensors can have the same characteristic that flows through each partial winding, in both cases the characteristics are compared with the same effect in both cases, although the mains currents are different ,
when connected to the windings in Therefore the circuit described above is that of the manner described above. The overload sensing device in three-phase motors is an explanation -is on the basis of a triangular special advantageous if it was given together with the circuit-switched motor. There io switching systems a is used, the above described, however, it can be seen that the teaching given has also been used.

to a star-connected motor. A cooling unit according to the invention allows

is reversible. so the use of refrigerated containers is easy

It can also be seen that when the relationship is certain to be in two different places with different

two assumed mains voltages is close to fö , 15 different mains voltages,

for example, if the available mains voltage is assumed in the above embodiment

on board a ship is 200 V, while it has been that the lower line voltage is 200 V and

If the destination country is 350 V, a three-phase motor the higher voltage is only 400 V. In general

can be operated satisfactorily at both locations, but the lower voltage can mean a tension

by connecting the partial windings of a voltage between 180 and 240 V, moreover

Delta to star connection is changed. In any higher voltage from 340 to 480 V for the

such a case when the overload sensors are used in the cooling unit according to the invention.

For this purpose 2 sheets of drawings

Claims (7)

1 93i IS 6 'claims: 1. Coolness for a container, with electric Motors connected to networks with voltages ν of two classes can be connected by simply switching the electrical connections of the windings of the motors, with a device that can be connected to the networks, which distinguishes between the two network voltage classes and through which the electrical connections of the windings of the motors can be switched to the nominal voltage of the Adapt motors to the mains voltage of the network to which the cooling unit is connected, characterized in that the device has two specially designed mains plugs (P ₁ JiP ₂ ) which do not fit into the socket of the other mains plug, that each mains plug has its own first switching unit downstream is that the two switch units are interlocked and that second switch units are provided for switching over the motor windings, which are combined with the first switch units to form a group switch (SS) . 2. Cooling unit according to claim 1, characterized in that the group switch (SS) has an additional pair of switches (W ₄ , L ₆ ) which are connected to the control circuit of electromagnetic contactors (Af5 ,, MS ₂ ) in order to control a connection , which adapts the nominal voltage of the contactors to the applied mains voltage, with main contacts of the contactors being provided between the first and second switch units, and that the additional pair of switches in the group switch is arranged so that the switches (H _x , L ₆ ) this additional pair are opened before opening the switch of the associated first and second switch unit and are closed after they are closed. 3. Cooling unit for a container, with electric motors that can be connected to networks with voltages of two classes by simply switching the electrical connections of the windings of the motors, with a device that can be connected to the networks that differentiates between the two network voltage classes and through which the electrical connections of the windings of the motors can be switched to adapt the nominal voltage of the motors to the mains voltage of the network to which the cooling unit is connected, characterized in that the device of electromagnetic contactors (MS _H , MS _L ) for switching the motor windings , a voltage sensing device, which is connected to the network power (R, S) of the cooling unit, and has several relays (MA ,, AfA ₂ ), ■ '-' djp do Efifegerspulen (MC ₁₁ , MC ₁ ) of the second electromagnetic contactors according to the detection of the voltage by the voltage . excite sensing device, and that the voltage sensing device comprises a transformer (Tr), Öer an; Netzleitüngen (ft> m is connected to the cooling unit and generates two sizes of secondary voltage, voltage, and voltage switching Relay (MR ₁ ) * in the second secondary connection (fc ₂ ) is connected to the smaller Sjjarfriufig of the transformer and switches quickly when the cooler is connected to a network? of the higher voltage class is connected, but does not switch if the bucket unit is connected to a network of the lower voltage class, and finally a relay (MAj) that switches slowly for each network voltage class and is connected to the secondary circuit (^ ₁ ) of the higher voltage of the transformer is, the two relays are locked against each other. 4. Cooling unit according to one of claims 1 to 3, characterized in that the motor windings have three phase windings through the second switch units or the Contactors for switching the motor windings can be switched between star and delta connection are. 5. Cooling unit according to one of claims 1 to 3, characterized in that the motor windings have three phase windings and that the phase windings are each two equal Have partial windings between series (Fig. 5a) and parallel connection (Fig. 5b) in each Phase through the second switch units or the contactors for switching over the Motor windings are switchable. 6. Cooling unit according to claim 5, characterized in that an overload sensor in series with one of the partial windings is connected in at least two phase windings (Fig. 5a, 5b). 7. Cooling unit according to claim 4, characterized in that an overload sensor in series with each of at least two phase windings is connected