Accidents occur in electrical networks, no matter how long ago they were installed. Because of this, voltage surges, phase imbalances are observed, and in some houses there is a constantly increased or decreased voltage level. There are different ways to protect against this phenomenon, one of which is to install an overvoltage and undervoltage release. Such a device is RMM-47, an overview of which, as well as a description of the characteristics and connection diagrams, are provided on the Samelektrik portal.
What it is
RMM-47 is an over/under voltage release. This is an additional device that works in conjunction with a load switch or circuit breaker. Its width is slightly less than 18 mm, which means that it takes up space equal to one module in the shield.
Its technical characteristics:
The main thing we need to pay attention to is the “Operation Voltage” characteristic:
- Minimum - 165 +-10% Volt.
- Maximum - 265 + -10% Volt.
This means that the release will operate when one of the specified limits is reached with an error of 10%, preserving the protected circuit.
The RMM-47 release does not have the ability to adjust the response threshold. All that is available to the user is the “RETURN” button to release the actuator and return the switching device to its original state.
AVR system
In the event of a prolonged absence of electrical power, a shutdown also occurs on the main electric motors. This is necessary to start the ATS (automatic transfer switch), and the production technology also requires it.
When the power supply to the sectional input is interrupted, the automatic system turns on the reserve, and the sectional switch is turned on, providing power supply from the backup source.
The minimum operating time of the ATS depends on the delay in the system that controls the input of the operating voltage, the operating time of the intermediate relays, the time intervals for turning off and turning on the switches of the working and backup input.
Purpose of the release
RMM-47 is used to protect electrical installations from high and low voltage. Most often, such situations arise as a result of zero burnout and phase imbalance in a three-phase network. This device does not protect against high-voltage surges in the network. Its purpose is to monitor the parameters of the power supply network and give a command to turn off the power to consumers.
Note: for protection against pulse surges there are specialized devices, for example, SPDs - various protective devices based on varistors.
Depending on the connection diagram, using the maximum and minimum voltage release RMM-47, you can organize protection of both specific electrical appliances and the entire facility as a whole by connecting the release to the input circuit breaker.
Minimum-overvoltage release PMM47 for IEK DIN rail
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Ways to receive orders
Pickup in Moscow - more details.
– There is no minimum order amount. – Moscow, Novokhokhlovskaya str., 91, building 10. –c 10.00
until
20.00
on working days in the Russian Federation.
Payment:
– cash upon receipt. – by bank card through the terminal. – bank transfer according to the issued invoice (payment is credited within 24 hours)
Delivery in Moscow - more details.
– The minimum order amount is 1000 rubles. – 300 rubles within the Moscow Ring Road. – from 10.00 to 18.00 on working days in the Russian Federation.
Payment:
– cash upon receipt. – bank transfer according to the issued invoice (payment is credited within 24 hours)
Delivery in the Moscow region - more details.
– The minimum order amount is 1000 rubles. – 500 rubles up to 10 km. from MKAD. – 40 rubles per 1 km. from the Moscow Ring Road + 300 rubles within the Moscow Ring Road, depending on the order amount. – from 10.00 to 18.00 on working days in the Russian Federation.
Payment:
– cash upon receipt. – bank transfer according to the issued invoice (payment is credited within 24 hours)
Delivery to cities of the Moscow region by Courier Service - more details.
– The minimum order amount is 1000 rubles. – Delivery to the Courier Service terminal in Moscow – Free. – All courier services are paid by the buyer. – Prepayment of the order by bank transfer against the account, payment for Courier Service services upon receipt.
Sending to Russian cities by Courier Service - more details.
– The minimum order amount is 1000 rubles. – Delivery to the Courier Service terminal in Moscow – Free. – All courier services are paid by the buyer. – Prepayment of the order by bank transfer against the account, payment for Courier Service services upon receipt.
Sending to cities of the Russian Federation by Transport Company - more details.
– The minimum order amount is 1000 rubles. – 300 rubles delivery to the Transport Company terminal in Moscow. – All services of the Transport Company are paid by the buyer. – Prepayment of the order by bank transfer against the account, payment for the services of the Transport Company upon receipt.
Ways to receive orders
– There is no minimum order amount. – Moscow, Novokhokhlovskaya str., 91, building 10. – from 10.00 to 20.00 on working days in the Russian Federation. – the order is paid upon receipt.
– The minimum order amount is 1000 rubles. – 300 rubles within the Moscow Ring Road. – from 10.00 to 18.00 on working days in the Russian Federation. – the order is paid upon receipt.
– The minimum order amount is 1000 rubles. – 500 rubles up to 5 km. from MKAD. – 40 rubles per 1 km. from the Moscow Ring Road + 300 rubles within the Moscow Ring Road, depending on the order amount. – from 10.00 to 18.00 on working days in the Russian Federation. – the order is paid upon receipt.
- Delivery to cities of the Moscow region by Courier Service - more details.
– The minimum order amount is 1000 rubles. – Delivery to the Courier Service terminal in Moscow – Free. – All courier services are paid by the buyer. – Prepayment of the order, payment for Courier Service upon receipt.
- Sending to Russian cities by Courier Service - more details.
– The minimum order amount is 1000 rubles. – Delivery to the Courier Service terminal in Moscow – Free. – All courier services are paid by the buyer. – Prepayment of the order, payment for Courier Service upon receipt.
- Sending to cities of the Russian Federation by Transport Company - more details.
– The minimum order amount is 1000 rubles. – 300 rubles delivery to the Transport Company terminal in Moscow. – All services of the Transport Company are paid by the buyer. – Prepayment of the order, payment for the services of the Transport Company upon receipt.
Ways to receive orders
– There is no minimum order amount. – Moscow, Novokhokhlovskaya str., 91, building 10. – from 10.00 to 20.00 on working days in the Russian Federation.
Payment:
– cash upon receipt. – by bank card through the terminal. – bank transfer according to the invoice (receipt occurs within 24 hours)
– The minimum order amount is 1000 rubles. – 300 rubles within the Moscow Ring Road. – from 10.00 to 18.00 on working days in the Russian Federation.
Payment:
– cash upon receipt. – bank transfer according to the invoice (receipt occurs within 24 hours)
– The minimum order amount is 1000 rubles. – 500 rubles up to 5 km. from MKAD. – 40 rubles per 1 km. from the Moscow Ring Road + 300 rubles within the Moscow Ring Road, depending on the order amount. – from 10.00 to 18.00 on working days in the Russian Federation.
Payment:
– cash upon receipt. – bank transfer according to the invoice (receipt occurs within 24 hours)
- Delivery to cities of the Moscow region by Courier Service - more details.
– The minimum order amount is 1000 rubles. – Delivery to the Courier Service terminal in Moscow – Free. – All courier services are paid by the buyer. – Prepayment of the order by bank transfer against the account, payment for Courier Service services upon receipt.
- Sending to Russian cities by Courier Service - more details.
– The minimum order amount is 1000 rubles. – Delivery to the Courier Service terminal in Moscow – Free. – All courier services are paid by the buyer. – Prepayment of the order by bank transfer against the account, payment for Courier Service services upon receipt.
- Sending to cities of the Russian Federation by Transport Company - more details.
– The minimum order amount is 1000 rubles. – 300 rubles delivery to the Transport Company terminal in Moscow. – All services of the Transport Company are paid by the buyer. – Prepayment of the order by bank transfer against the account, payment for the services of the Transport Company upon receipt.
Installation features
Unlike a voltage relay, the RMM-47 release does not have its own power contacts, therefore the rated current is not indicated in the characteristics. It is an attachment or additional device to circuit breakers and load switches.
To do this, there is a hole on the side of most circuit breakers that allows the connection of additional devices. In the photo below you can see how to access it. To do this, you need to turn the plug and remove it from the seat.
In the window you can see part of the circuit breaker's charging mechanism. On the left side of the RMM-47 there is a protruding pin for the mechanical connection of the release with the drive of the power contacts of the automatic machines and load switches.
This determines the operating principle of the RMM-47 release:
- The electronic control board analyzes the current voltage in the network and compares the value with the settings set by the manufacturer.
- In case of deviation beyond the permissible norms, it sends a control signal to the solenoid, which in turn is mechanically connected to the drive for connecting the circuit breaker.
- Accordingly, along with the activation of the release solenoid, the mechanically connected disconnector will turn off. To return the devices to their original state and supply energy, you need to press the “RETURN” button and reset the circuit breaker flag.
The following video clearly demonstrates the principle of installation of such attachments for switching protective devices:
Stages of operation of the protective valve
1st stage
The system is triggered when the voltage drops to 70% of the nominal value and with a time delay of half a second.
When the first stage of protection is turned on, electric motors less important for production are turned off. A further decrease in one of the main parameters, which ensures the possibility of self-starting of the main mechanisms, is prevented.
2nd stage
The next stage fires after the first stage operates. The second setting has 50% of the nominal potential difference, the response time is nine seconds.
Self-starting of the main electric motors does not occur; the remaining mechanisms connected to the protection circuit are turned off, but the operation of the units is maintained, the shutdown of which will lead to an emergency. The second stage provides safe braking and stopping mode.
Recommended connection diagram
RMM-47 is connected to the phase coming out of the circuit breaker to which it is also connected. This is the drawing shown in the official technical documentation for the product made by IEK.
In practice, the connection diagram for RMM-47 in a single-phase network is as follows:
The connection diagram for a three-phase network is almost similar:
This connection is due to the fact that if you take the phase before the circuit breaker, the devices will still be protected, but the release coil may fail, as proven by repeated experiments of specialists. The result is a picture like this:
When connected according to the connection diagram above, this will not happen, since the release circuit will also be de-energized.
