
Technical Specifications
E-52
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames E & F
Auxiliary Power Supply Load Requirements
This table lists the auxiliary power supply requirements for the 890 units and ancillary equipment,
assuming normal operating conditions with maximum SMPS and fan loads.
Keypad
6901 Keypad
1W
6911 Keypad
1W
Worked Example
To calculate the total requirement for an 890CS Frame D fitted with a 6511 keypad:
Power = 24 + 10.2 (fan load) + 0.9 = 35.1W, Input Current @ +24V = 35.1 / 24 = 1.463A
IMPORTANT
The 890CS unit's in24V SMPS has a 3A current limit which is used during start-up.
In a system containing two 890CS units for example, the initial loading will be 2 x 3A for approximately 50ms during
start-up, i.e. 6A. Consequently, the customer auxiliary SMPS +24V power supply must be able to over-load for a brief
time to accommodate the start-up condition.