Safety features for electric vehicle control

An electric vehicle comprising:

• a direct current drive motor;
• a separately excited field winding disposed within said direct current drive motor;
• a direct current power supply;
• connecting means for connecting said direct current power supply to the armature of said direct current drive motor;
• a throttle connected to supply a signal proportional to its positioning;
• field control means connected to said throttle and said separately excited field winding for supplying field excitation in response to the signal from said throttle;
• a brake connected to said field control means for cancelling any throttle signal and demanding a regenerative armature current when depressed;
• and
• motor overspeed control means connected to said field control means for limiting the maximum speed of said direct current drive motor by causing said field control means to supply a predetermined field current to said separately excited field winding when the speed of said direct current drive motor exceeds a predetermined value.

An electric vehicle comprising:

• a direct current drive motor;
• a separately excited field winding disposed within said direct current drive motor;
• a direct current power supply for powering said electric vehicle;
• armature current sensing means connected to said direct current drive motor for sensing the value of armature current flowing through said direct current drive motor;
• field control means connected to said separately excited field winding for supplying field excitation;
• armature current limiting means connected to said armature current sensing means and said field control means for causing said field control means to apply full-field current to said separately excited field windings when armature current exceeds a predetermined level;
• connecting means switchable between a closed position supplying power to said direct current drive motor and an open position disconnecting said direct current power supply from said direct current drive motor in response to a signal from said armature current limiting means;
• said armature current limiting means connected to supply a signal to said connecting means causing said connecting means to switch to the open position when armature current exceeds a predetermined level;
• and,
• a time delay connected between said armature current limiting means and said connecting means to delay the signal from said armature current limiting means to said connecting means so said connecting means is switched to the open position a predetermined time after said armature current exceeds and remains above a predetermined level.

An electric vehicle comprising:

• a direct current drive motor;
• a separately excited field winding disposed within said direct current drive motor;
• a direct current power supply for powering said electric vehicle;
• armature current sensing means connected to said direct current drive motor for sensing the value of armature current flowing through said direct current drive motor;
• field control means connected to said separately excited field winding for supplying field excitation;
• armature current limiting means connected to said armature current sensing means and said field control means for causing said field control means to apply full-field current to said separately excited field windings when armature current exceeds a predetermined level;
• throttle means providing an output signal proportional to positioning of said throttle means;
• switching means connecting the signal of said throttle means to said field control means and being switchable between a closed position feeding the output signal of said throttle means to said field control means and at an open position blocking the signal from said throttle means to said field control means;
• and,
• said armature current limiting means providing an output signal to said switching means to switch said switching means to the open position when said armature current exceeds a predetermined level.

An electric vehicle comprising:

• a direct current drive motor;
• a separately excited field winding disposed within said direct current drive motor;
• field control means connected to said separately excited field winding for supplying field excitation;
• said field control means supplying selected current pulses in response to throttle settings and vehicle operating parameters to said separately excited field windings;
• minimum field current supply means connected to said field control means causing said field control means to supply current pulses having some minimum predetermined duration;
• maximum field current supply means connected to said field control means for limiting field current to some maximum value;
• a direct current power supply;
• connecting means for connecting said direct current power supply to said direct current drive motor;
• and,
• full-field means connected to said field control means causing said field control means to supply a selected field current to said separately excited field windings before said connecting means connect said direct current power supply to said direct current drive motor.

An electric vehicle comprising:

• a direct current drive motor;
• a separately excited field winding disposed within said direct current drive motor;
• field control means connected to said separately excited field winding for supplying field excitation;
• said field control means supplying selected current pulses in response to throttle settings and vehicle operating parameters to said separately excited field windings;
• minimum field current supply means connected to said field control means causing said field control means to supply current pulses having some minimum predetermined duration;
• throttle means comprising a throttle pedal and providing a signal proportional to said throttle pedal setting to said field control means;
• and,
• said throttle means comprising throttle release means connected to said field control means causing said field control means to supply regenerative armature current when said throttle pedal is less than a predetermined amount depressed.

An electric vehicle comprising:

• a direct current drive motor;
• a separately excited field winding disposed within said direct current drive motor;
• a direct current power supply;
• connecting means for connecting said direct current power supply to the armature of said direct current drive motor;
• temperature sensing means connected to said direct current drive motor for sensing the temperature of said direct current drive motor and providing an excess temperature output signal when the temperature of said direct current drive motor exceeds a predetermined value;
• a throttle,
• field control means connected to said throttle and said separately excited field winding for supplying field excitation in response to a signal from said throttle and,
• said temperature sensing means being connected to reduce the value of the maximum armature current which can be supplied.