MANUAL# 5005-2040-000-F UPDATED: 6/1/2021
5
APPLICATION NOTE
POWER DISSIPATION CONSIDERATIONS AND CALCULATIONS WHEN USING
LINEAR DC SERVO DRIVES:
When selecting a linear Drive, the following ratings of the Drive should be known in order to
properly size the Drive to your system requirements:
1
– The total wattage, peak current, and voltage rating of all the semiconductors installed on the
heat sink of the output power stage of the Drive.
Output transistor ratings for the SMA5005 series are:
Voltage: 250 Volts
Peak current: 60 A; Continuous current: 30 A (Normally shipped with 12-20A limit)
Total wattage @25 deg C.:1200 Watts
Output transistor ratings for the SMA5015 series are:
Voltage: 200 Volts
Peak current: 240 A; Continuous current: 60 A (Normally shipped with 20-50A limit)
Total wattage @25 deg C.:4480 Watts
The SMA5005 series Drive is a module requiring an external unregulated single polarity DC power
supply. Glentek offers various unregulated power supplies for the SMA5005 series Drives.
The SMA5005 series Drive is also available in multi-axis configurations. That is, there are two
basic baseplate assemblies namely 2-axis and 4-axis baseplate assemblies that have built-in AC
to DC power supplies (un-regulated) and cooling fans. The 2-axis baseplate assembly contains
one AC to DC power supply, one fan, and up to two SMA5005 Drive modules. The 4-axis
baseplate assembly contains one AC to DC power supply, two fans, and up to four SMA5005 Drive
modules. For multi-axis applications, it is always recommended to use three phases power
transformers for minimizing ripple voltage during high current demand scenarios where all axis
motors are running at full load simultaneously. Glentek offers various isolated three phases power
transformers.
The SMA5015 series is a stand-alone style Drive, meaning that the unregulated dual polarity
power supply is mounted within the Drive enclosure. Glentek offers 1.4KVA and 2.0KVA center
tapped power transformers for the SMA5015 series Drives.
2
– Typical continuous internal power dissipation rating of the Drives running at normal room
conditions is:
SMA5005-xLB series (L-bracket heatsink); 100 Watts continuous
SMA5005-xSF series (short fin heatsink); 250 Watts continuous
SMA5015 series; 300 Watts continuous
For most applications, the above heat sinking is adequate. However, if you have a usage mode
where the heat sink temperature becomes excessive, please contact Glentek and we can furnish a
larger heat sink with greater air flow for your application.
