Editing Motor peak and continuous current limits
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All GD motor drives feature a two stage current limit in order to protect motor and drive from overheating damage. | All GD motor drives feature a two stage current limit in order to protect motor and drive from overheating damage. | ||
− | == | + | ==Descroption of operation== |
The basic parameters for current limiting are: | The basic parameters for current limiting are: | ||
− | * | + | *[[MMC]] Motor maximum current a.k.a. motor peak current |
− | * | + | *[[MCC]] Motor continuous current a.k.a. motor continuous current |
− | * | + | *[[MTC]] Motor thermal constant time |
*Peak current time limit ''T'', normally a fixed value of 1 or 2 seconds depending on drive model | *Peak current time limit ''T'', normally a fixed value of 1 or 2 seconds depending on drive model | ||
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[[File:Currentlimits graph.png|800px]] | [[File:Currentlimits graph.png|800px]] | ||
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In ideal case drive would output the demanded current always. However due to the fact that motor and drive generates more heat when current is higher, it is necessary sometimes to reduce output current to a safe level. | In ideal case drive would output the demanded current always. However due to the fact that motor and drive generates more heat when current is higher, it is necessary sometimes to reduce output current to a safe level. | ||
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* Drive outputs demanded current infinitely if demand is below MCC level | * Drive outputs demanded current infinitely if demand is below MCC level | ||
* Drive outputs demanded current if demand is below MMC and time limit T has not been exceeded | * Drive outputs demanded current if demand is below MMC and time limit T has not been exceeded | ||
− | * Drive | + | * Drive reduces ''T'' based on thermal time constant (MTC) if calculated motor temperature is already at maximum safe level |
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