Ramp Section of a DC drive....















This section of the electronics in a dc drive makes it possible to accelerate and decelerate the dc motor as per desired acceleration and deceleration rates. Two adjustments called Ramp UP and Ramp Down times are normally made avaialbe to the user. Typically values from zero to 120 seconds are possible. The circuit is normally based around two operational amplifiers and capacitors to achieve the function. Shown above is a typical ramp circuit found in analog dc drives.



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Block Diagram



Ramp Circuit


Speed Amplifier


Current Amplifier


 Firing Circuit


Power Circuit


Types of DC drives 



 Checking Thyristor


Voltage feedback Vs Tacho feedback


Current Limit


Constant HP & constant Torque


Field Weakening


Using CRO 



Motor runs at full speed


Fuses Blow


Hunting in speed


Motor gives jerks


Belts vibrate


Speed control not satisfactory 



Speed drops on load


Motor overheats


Sparking on commutator


DC drives and Power Factor


Your comments and suggestions 


Drive stops all of a sudden 


Motor not able to drive the load


DC to DC isolation


 Motor or Drive?