Alfa-2: total load during transmission
Radio in anticipation consumes significantly less than in the transmission. Therefore, the quiet operation of the post after switching on does not show that one power supply unit will withstand two-way radio and other devices simultaneously. For the NavCom Alfa-2, it is useful to first map the operating modes: who is on all the time, who is added during transmission, and what processes may coincide. Then the choice of source is based on the real load, not on the number of connectors or inputs.
Consider a common output, not two inputs
The manufacturer describes Alfa-2 as an alternative power supply of 220 V AC and 24 V DC. The presence of two inputs does not double the permissible output current. In the guide NADS.436537.025 RE for the output specified a maximum of 10 A at one hundred percent cycle. This is the total source limit, not the individual ten amps for each connected device.
First, take the passport currents of consumers in the right modes. For two-way radio you need at least a reception and transmission with the intended settings. For other devices, a constant load and, if required by their documentation, triggering processes are taken into account. The input current of the Alfa-2 itself cannot be substituted instead of the permissible load of its output.
An example in which waiting hides a problem
For example, a two-way radio consumes 0.7 A on reception and 8 A on transmission. Another device requires 1.5 A, the third - 1 A. Values are fictitious to explain the calculation and are not characteristics of specific commodities. At reception it turns out 3.2 A, in the transmission - 10.5 A. One and the same post goes through a calm mode and goes beyond 10 A in the other.
| Conditional consumer | Two-way radio reception | Two-way radio transmission |
|---|---|---|
| Two-way radio from an example | 0.7 A | 8 A |
| Permanent device A | 1.5 AA | 1.5 AA |
| Permanent device B | 1 A | 1 A |
| Total load | 3.2 A | 10.5 A |
| Comparison with limit 10 A | Below this limit; other checks are required | Above the specified limit; the scheme requires change |
You can’t correct the result by averaging the conversation time. If the permissible source current is exceeded for the selected mode, another power supply option or load redistribution is needed. The specific current reserve, temperature conditions and permissible start-up processes are selected by the designer according to the documentation; the universal percentage of the reserve is not assigned here.
The voltage is checked before the final choice.
There is a significant feature of the Alfa-2 documentation: section 1.1.2 of the available manual calls 13.5 V, and its table and indication description use 12 V. Therefore, the calculation in amperes does not confirm compatibility in voltage. For the proposed configuration, you need to agree on the output value of the passport and the permissible limits of each connected device.
If one consumer is designed for another power supply line, the coincidence of a convenient connector does not solve anything. You can’t add it to a group just because it’s standing next to you. Also, the presence of a backup input should not be considered a promise of charging batteries: the tasks of power supply consumers and battery charge are agreed separately.
Check the voltage of the consumer
Even a suitable source does not cancel the losses on the line. The length, cross-section of the wires and connections affect the voltage directly near the apparatus, especially when the current is increased. Therefore, the project transfers not only the amount of amperes, but also the length of cable tracks. The measurement at the terminals of the block and the measurement at the two-way radio refer to different points in the system.
The final selection goes through several stages: instrument modes, the sum of simultaneous currents, comparison with the output limit, checking voltage and cables. If the test does not pass at one stage, the neighboring successful result does not compensate for it. Sufficient source current does not correct the wrong power supply of the consumer, and a short cable does not increase the permissible load of the unit.
Buy a block for an agreed group of devices
The current Alfa-2 price is shown in its product card. Condition, availability, options and composition are confirmed in the quotation. The photo shows the body of the unit with indication and cable inputs; external battery, radio and load distribution are not included in the depicted object.
Send a list of devices with consumption modes, their permissible power supply, line lengths and available primary sources. Specify whether multiple transmitters can operate simultaneously. According to this information, we agree on Alfa-2 or another option for the task, scope of supply and delivery to your region. Number, city and details will allow you to prepare a quotation for a specific system.
Total loadLoad operating modes → total simultaneous current → power supply output limit
Devices and linesPower supply → individual loads; check voltage and cable voltage drop for each circuit
Devices are shown by separate semantic branches, not by a successive connection. This is an explanatory calculation scheme, not a mounting instruction.
Questions before buying
Two Alfa-2 inputs give two separate 10A outputs?
Nope. In the manual, the maximum output current is specified for the source as a whole. The inputs 220 V AC and 24 V DC refer to the primary power supply selection.
Can you calculate power supply from two-way radio?
It is necessary to take into account the transfer and possible simultaneous operation of other consumers. An example of the article shows how the allowable waiting load becomes an excess on the transmission.
Do all Alfa-2s have the same output voltage?
In the available manual, there is a discrepancy between 13.5 V in the description and 12 V in the table. The parameter is coordinated according to the passport of the proposed configuration and the requirements of consumers; the general inscription “12 V” is not enough.
The main product in our catalog
NavCom Alfa-2
See the product card for the current price. availability and composition are confirmed in the quotation. The status, options and composition are confirmed in the quotation.
Request a quoteDocumentation: NavCom ALFA2, NADS.436537.025RE, PDF16s, §1.1-1.2 p4-5, §2.2-2.3p8-9, §3p11-12; Official NavCom Alfa-2 card, fresh reading stock-trio220-evidence/alfa-primary-product.html. These provisions relate to these editions; the applicability to the proposed configuration is specified separately.