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Safety information
Introduction
6.3.2
Cooling requirements for higher output frequencies
Single OTL output sharing chokes - OTLX0X
Up to output frequencies of 300 Hz, 1 m/s airflow provides adequate cooling.
Above 300 Hz, the following equation must be used to calculate the required airflow:
0.75
S = (f
/72)
Where:
S is the airflow in metres per second
f is the drive output frequency in Hz
Example:
Output frequency is 450 Hz
0.75
S = (450
/72)
= 1.4 m/s
Dual OTL output sharing chokes - OTLX1X
The OTLX1X dual output sharing choke core does not see the change in drive output frequency as this choke is a current cancelling choke. Only the
drives switching frequency has an affect on the core loss.
Therefore motor frequency is not an issue until higher frequencies cause high copper losses due to skin effect.
Therefore with the dual OTL chokes, only 1 m/s airflow is required.
Maximum output frequency for OTL chokes
The maximum allowable output frequency for OTL output sharing chokes, singles or duals, should be limited to 1000 Hz.
6.4
Supplying the Unidrive M/Unidrive HS size 9A, 9D, 10D and 11D drives with DC / DC
bus paralleling
The drive may be supplied with DC instead of 3 phase AC.
The connecting of the DC bus between several drives is typically used to:
1.
Return energy from a drive which is being overhauled by the load to a second motoring drive.
2.
Allow the use of one braking resistor to dissipate regenerative energy from several drives.
There are limitations to the combinations of drives which can be used in this configuration.
For further information, contact the supplier of the drive.
NOTE
It is not possible to supply Unidrive M/Unidrive HS size 9E/T, 10E/T and 11E/T drives with DC due to the lack of an accessible negative DC terminal.
6.5
Heatsink fan supply
When operating on normal mains supply the heatsink fan on all drive sizes is supplied internally by the drive. When operating in low voltage mode it
is necessary to connect an external 24V supply to terminal 61 and 62 if heatsink fan operation is required. Please see section 6.7 Low voltage
operation on page 98 for more details.
6.6
24 Vdc supply
The 24 Vdc supply connected to control terminals 1 & 2* provides the following functions:
•
It can be used to supplement the drive's own internal 24 V supply when multiple option modules are being used and the current drawn by these
module is greater than the drive can supply.
•
It can be used as a back-up power supply to keep the control circuits of the drive powered up when the line power supply is removed. This allows
any fieldbus modules, application modules, encoders or serial communications to continue to operate.
•
It can be used to commission the drive when the line power supply is not available, as the display operates correctly. However, the drive will be in
the Under voltage state unless either line power supply or low voltage DC operation is enabled, therefore diagnostics may not be possible.
(Power down save parameters are not saved when using the 24 V back-up power supply input).
•
If the DC bus voltage is too low to run the main SMPS in the drive, then the 24 V supply can be used to supply all the low voltage power
requirements of the drive. Low Under Voltage Threshold Select (06.067) must also be enabled for this to happen.
NOTE
On size 9 and larger, the power 24 Vdc supply (terminals 51, 52) must be connected to enable the 24 V dc supply to be used as a backup supply,
when the line power supply is removed. If the power 24 Vdc supply is not connected none of the above mentioned functions can be used, "Waiting
For Power System" will be displayed on the keypad and no drive operations are possible. The location of the power 24 Vdc can be identified from
Figure 6-16 Location of the 24 Vdc power supply connection on size 9 to 11 on page 97
96
System
Product information
configuration
Mechanical
Electrical
Installation
Installation
Unidrive M / Unidrive HS Modular Installation Guide
Technical data
UL Information
Issue Number: 5
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