Datasheet

POWER SUPPLY CONNECTION
TERMINAL 1 Power Ground
Connect the power supply ground to this terminal
TERMINAL 2 Power (+)
Connect the power supply “+” to this terminal
The power supply voltage must be between 15VDC and 50VDC. The maximum power supply current required is 67% of the
motor’s rated phase current. An unregulated power supply may be used as long as the voltage stays between the limits; keep the
ripple voltage to 10% or less for best results.
CAUTION! Power supply voltage in excess of 50VDC will damage the G251.
CAUTION! Never put a switch on the DC side of the power supply! This will damage, if not destroy, your drive!
A very accurate calculation of maximum power supply voltage is to find your motor’s inductance, and put it into the following
equation.
32 * (√mH inductance) = Power Supply Voltage
If your motor has 2mH of inductance, the equation would look as follows.
32 * (√2) = 45.12V
In the example above 45.12V is the maximum voltage for that specific motor; any voltage above this will create unnecessary
heating and any voltage below that will get you proportionally less speed than you could otherwise get at 45.12V.
CURRENT SET RESISTOR
TERMINAL 3 Current Set
Connect the current set resistor to this terminal.
TERMINAL 4 Current Set
Connect the other end of the current set resistor to this terminal.
This input programs the G251’s current output to the motor windings. The current set resistor is a linear calculation of 1K ohms of
resistance for every amp of motor winding current. This means that a 2.3A per phase motor will require a 2.3K ohm resistor on
terminals 3 and 4. If your motor is 3.5A or above you can leave these terminals open and the drive will self-limit to 3.5A; however,
you will lose the auto current reduction feature of the drive. If you require this feature then a 3.5K resistor should be put on the
drive. This can be a standard 1/4W resistor, though any resistor larger than 1/8W can be used.
MOTOR CONNECTION
TERMINAL 5 Phase A
Connect one motor winding to this terminal
TERMINAL 6 Phase /A
Connect the other end of the winding to this terminal
TERMINAL 7 Phase B
Connect the other motor winding to this terminal
TERMINAL 8 Phase /B
Connect the other end of the winding to this terminal
Connect one motor winding to terminals 5 and 6. Connect the other winding to terminals 7 and 8. Turn the power supply off when
connecting or disconnecting the motor. If the motor turns in the wrong direction, reverse the motor winding connections to terminals
5 and 6.