Electric traction control
The traction electric drive control circuit does not differ from the lifting circuit, therefore it is not presented here. The four-motor electric swing drive of the ESh-1590A excavator is controlled according to a scheme similar to the lifting scheme, but its principal feature is the presence of a reverse mitigation unit. The purpose of the reverse softening unit was explained above, when.
However, structurally, this unit, in this scheme, is made somewhat differently than in the scheme. Here, the PMUV-3 winding in all modes, except for reverse braking, provides a weak negative feedback on the generator voltage, which, due to the presence of a 2KSV capacitor, contains a component of a flexible negative voltage connection.
In these modes, the resistance circuit 6SUV is open, since the 5VGV (6VGV) valve is included in the circuit of the closed reverse contact RPVV (RPNV), which excludes the flow of current at a given polarity of the generator. When braking by reverse, the polarity of the generator voltage remains the same, and the reversing contacts are switched and the 6SUV resistance is connected to point a of the ZSUV potentiometer.
Considering the circuit of the voltage feedback node for the reverse braking mode, we can conclude that in this case the PMUV-3 winding is included in the diagonal of the bridge formed by the gab, gbe, 6SUV and SDVZ resistances. By selecting the 6SUV resistance, it is possible to vary the voltage feedback within a wide range. So, if you select it from the condition Schemes of protection units on the ESh-1590A excavator are similar to the same units on the ESh-1590 excavator.
Circuits with magnetic cut-off for current Excavator EKG-8 Generators for lifting GP, head of GN and turning GVH of excavator EKG-8 are independently excited from power three-phase magnetic amplifiers MUP, EKG and MUV, which have a bridge circuit for switching on the load. The swing generator is used to power the travel motor when traveling..
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