Networking / Colocation: Baetech ATS (Automatic Transfer Switch) testing for Cisco/single Powered Devices
Below details the testing of an Baetech ATS-11 series (ATS18A-30) ATS (Automatic Transfer Switch). The networking rack houses some devices that contain only one power supply. The main focus of testing this unit was to provided failover power capabilities to our stacked network switch cluster (Cisco 3750G). A few options were out there for lower (Amps) but would not work for our implementation. Cisco Redundant Power System were also evaluated, but were limited in their abilities. From what I remember, 6 devices could be plugged in, but the RPS would only be able to power 3 of the 6 devices. This would mean we would have to use 2-3 of these units to actually be fully backed up.
230 VAC, 30 Amp ATS with RS232 access
ATS18A-30 Specifications
| Number of inputs: | 2 |
| Circuit breakers/input: | 2-30A |
| Total output receptacles: | 2 |
| Total rebootable receptacles: | 0 |
| Phases: | 1 |
| Vertical unit: | NO |
| Current sensors: | 1 |
| Voltage sensors: | 2 |
| Power Measurment: | YES |
| nternal temperature sensor: | YES |
| RS232 (serial) access: | YES |
| Ethernet access: | NO |
The power input (2) on this unit (to the floor) are NEMA L6-30P (twist lock) plugs. We already had APC vertical PDUs in our racks and wanted to be able to integrate them with the ATS solution. This model contains NEMA L6-30R (2 female sockets) that allowed the APC metered PDUs to be plugged directly in.
Testing information
Due to limited resources for testing, only a 6 amp load was placed on the ATS switch. The following devices were used:
| Quantity | Device |
| 2 | APC vertical 208V Metered PDUs Model AP7841 |
| 5 | IBM System X servers |
| 1 | Cisco 3750G |
| 2 | Dell PowerConnect 5224 switches |
Initial login to the ATS system.
ATS-11 Series
(C) 2003 by BayTech
F3.04
Option(s) Installed:
True RMS Current
Internal Temperature
True RMS Voltage
Unit ID: ATS18A-30
Input Power Source: 1
Average Power: 10 Watts
True RMS Voltage 1: 209.1 Volts
True RMS Voltage 2: 208.3 Volts
True RMS Current: 0.0 Amps
Maximum Detected: 0.1 Amps
Internal Temperature: 29.5 C
Type "Help" for a list of commands
Below lists the commands that can be used while the serial mode is set to console on the ATS unit.
ATS-11>help Status --ATS-11 Status Config --Enter configuration mode Source n --Select the input power source, n=1 or 2 Current --Display True RMS Current Clear --Reset the maximum detected current Temp --Read current temperature Voltage --Display True RMS Voltage Logout --Logoff Logoff --Logoff Exit --Logoff Password --Changes the current user password Whoami --Displays the current user name Unitid --Displays the unit ID Help --This Command Type "Help" for a list of commands
Information before attaching the devices
ATS-11>status
Input Power Source: 1
Average Power: 6 Watts
True RMS Voltage 1: 209.1 Volts
True RMS Voltage 2: 208.3 Volts
True RMS Current: 0.1 Amps
Maximum Detected: 0.1 Amps
Internal Temperature: 29.5 C
After attaching devices
ATS-11>
Unit ID: ATS18A-30
Input Power Source: 1
Average Power: 1101 Watts
True RMS Voltage 1: 208.7 Volts
True RMS Voltage 2: 208.8 Volts
True RMS Current: 5.9 Amps
Maximum Detected: 6.0 Amps
Internal Temperature: 30.0 C
Start of testing
ATS-11>current True RMS Current: 5.7 Amps Maximum Detected: 6.0 Amps
Below shows that we are currently running on power source 1
ATS-11>status
Input Power Source: 1
Average Power: 1034 Watts
True RMS Voltage 1: 208.8 Volts
True RMS Voltage 2: 208.9 Volts
True RMS Current: 5.7 Amps
Maximum Detected: 6.0 Amps
Internal Temperature: 30.0 C
After failover test of source 1, below shows that the unit was failed over to the second power leg. This was completely transparent to ALL devices.
ATS-11>status
Input Power Source: 2
Average Power: 1014 Watts
True RMS Voltage 1: 0.4 Volts
True RMS Voltage 2: 208.2 Volts
True RMS Current: 5.7 Amps
Maximum Detected: 6.0 Amps
Internal Temperature: 29.5 C
Power source 1 was reconnected. The unit continued to run on source 2. For testing, source 2 was failed. As shown below, the unit automatically failed back over to source 1.
ATS-11>status
Unit ID: ATS18A-30
Input Power Source: 1
Average Power: 1032 Watts
True RMS Voltage 1: 208.8 Volts
True RMS Voltage 2: 0.6 Volts
True RMS Current: 5.7 Amps
Maximum Detected: 6.0 Amps
Internal Temperature: 30.0 C
Details one more time of current Amps.
ATS-11>current True RMS Current: 5.6 Amps Maximum Detected: 6.0 Amps
This unit has the ability to manually failover the power source via the console. Below confirms this ability. The input power source is currently 1.
ATS-11 Series
(C) 2003 by BayTech
F3.04
Option(s) Installed:
True RMS Current
Internal Temperature
True RMS Voltage
Unit ID: ATS18A-30
Input Power Source: 1
Average Power: 1027 Watts
True RMS Voltage 1: 208.7 Volts
True RMS Voltage 2: 208.9 Volts
True RMS Current: 5.6 Amps
Maximum Detected: 6.0 Amps
Internal Temperature: 30.0 C
Using the “source” command, the unit is manually failed over to the other power source.
ATS-11>source 2
Unit ID: ATS18A-30
Input Power Source: 2
Average Power: 956 Watts
True RMS Voltage 1: 209.6 Volts
True RMS Voltage 2: 208.1 Volts
True RMS Current: 5.7 Amps
Maximum Detected: 6.0 Amps
Internal Temperature: 30.0 C
Results:
All testing was completed without error. None of the devices reported any power problems or errors. The following were monitored:
- Each server via the RSA logging interface
- Cisco catalyst logs
- PDU interface and logs
- Visual inspection to check for booting indicators
The ATS was failed over from power source 1 to 2 without issue. Next source 1 was brought back online, and source 2 was failed. The switch failed back to source 1. Source 2 was brought back up and source 1 was failed again. This was performed approximately 5 times for verification. Also, manual failover utilizing the ATS serial console was performed without issue.
Notes: So this really works. I was somewhat sceptical initially, but now I am ready to put it into production. This is a great option for providing redundant power paths for servers or networking equipment that only has one power supply. I know that the single power supply units are still not truly redundantly powered, but at least this gives that single power fed unit a better chance. In this implementation, the power sources are redundant pathed under the floor at the colocation. This would work great also for a small office. Just feed one PDU to commercial building power and the other to a UPS unit.
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