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NI SMD-7613/7614/7615/7616 User Manual
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© National Instruments
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5
Connecting the Power Supply
If you need information about choosing a power supply, refer to
Choosing a Power Supply
.
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Connect the power supply “+” terminal to the connector terminal labeled “V+”.
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Connect power supply “-” to the connector terminal labeled “V-”.
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The green ground screw on the corner of the chassis should be connected to earth ground.
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Use 18 or 20 gauge wire.
The NI SMD-761x drives contain an internal fuse that connects to the power terminal.
This fuse is not user replaceable. If you want to install a user serviceable fuse in your system,
install a fast acting, 7 A fuse in line with the + power supply lead.
Caution
Do not reverse the wires. Reversing the connection will destroy your drive
and void your warranty.
If you plan to use a regulated power supply you may encounter a problem with regeneration. If
you rapidly decelerate a load from a high speed, much of the kinetic energy of that load is
transferred back to the power supply. This can trip the overvoltage protection of a switching
power supply, causing it to shut down. NI offers the SMD-7700 regeneration clamp to solve this
problem. If in doubt, buy an SMD-7700 for your first installation. If the regen LED on the
SMD-7700 never flashes, you do not need the clamp.
Choosing a Power Supply
When choosing a power supply, there are many things to consider. If you are manufacturing
equipment that will be sold to others, you probably want a supply with all the safety agency
approvals. If size and weight are an issue, get a switching supply.
You must decide what size of power supply (in terms of voltage and current) is needed for your
application.
National Instruments offers two power supplies that are excellent matches for the NI SMD-761x
drives: PS-12 24V, 6.3A) and PS-13 (48V, 6.7A).
Voltage
The motor can provide more torque at higher speeds if a higher power supply voltage is used.
Refer to the
Torque Speed Curves
section for guidance.
If you choose an unregulated power supply, make sure the no load voltage of the supply does not
exceed the drive’s maximum input voltage specification.