Unable to Recharge the prepaid meter

Solution: Connectivity Check: Confirm the meter is successfully communicating with the server. Serial Number Verification (SmartComm): Access the SmartComm Customer Master and ensure the serial number recorded matches the physical serial number of the connected meter. Duplicate Configuration Check: Verify that no two meters are incorrectly configured with the exact same serial number in the system.

Email Configuration SMTP Details Outlook

Solution: SMTP Host/Server Name: For Outlook.com: smtp-mail.outlook.com For Office 365/Microsoft 365: smtp.office365.com SMTP Port:587 (recommended) Encryption Method: STARTTLS Authentication: Your email account needs to be authenticated, so enable login or use the ""My outgoing server (SMTP) requires authentication"" option in your email client. Username: Your full Outlook email address (e.g., yourname@outlook.com or yourname@domain.com) Password: Blank

Email Configuration App Password creation for Gmail account

Reason - Gmail will work only with a secure encrypted app password Solution: Go to your Google Account settings. Navigate to the Security tab. If you don't have it enabled, turn on Two-Step Verification. Find and click on App passwords. Select an app name (like ""SMTP"" or ""Mail Client"") and click Generate. Copy the generated 16-character password and use it in your mail client's password field instead of your main Gmail password.

Email Configuration SMTP Details Gmail

Solution: Gmail SMTP Settings SMTP Server: smtp.gmail.com Port: 587: (requires STARTTLS/TLS) 465: (requires SSL) Authentication: Required Username: Your full Gmail address (e.g., user@gmail.com) Password: An App Password generated from your Google Account security settings Security/Connection: TLS or SSL, depending on the port chosen

Transfer existing sensor to a different gateway

Reason - Loss of old data stored under device id created Solution: To prevent data loss, edit the sensor and use the "Move to Gateway" option to transfer the sensor to a different gateway.

Asset list is not available in the filter

Reason - The asset is not assigned to the organization Solution: Check the asset selection settings in organization settings

Reason - Sensor/gateway limit exceeded Solution: Check license information for sensor/gateway limit

Cannot change the ip address of gateway

Reason - The ip address should is not available Solution: 1. if company network is being used check the accesibility to access 2. check if set ip is with in subnet range 3. Check if Primary and Secondary DNS is correct as per network settings 4. Set the Default Gateway IP to match the router's IP or the company network's default gateway IP.

3rd part meter not communication

Reason - 1. Memory map configuration wrong 2. (10 power -4 )Conversion factor is not available in third party memory map configuration 3. Data on modscan and software is matching but not matching with meter display readings Solution: 1. Verify data via Modscan, check wiring, confirm the meter parameter's datatype/function code in the memory map, and ensure the gateway supports that parameter datatype. 2. Can be added from conversion factor available in Master settings

Could not download certificate

Reason - All mandatory fields are not saved in organisation info settings Solution: All details should be given in mandatory field of organisation settings

Discharge Resistors

Updated: Sep 08, 2026 | 6 min read

Technical Articles

Published: Jul 14, 2026 by Abhinav L Purkar

Technical Articles

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Typically, power factor correction capacitors are fitted with discharge resistors connected directly across the terminals (two resistors between three phases). These resistors are mandatory safety requirement recommended by the capacitor standards, to discharge the residual voltage that remains in the capacitor, once it is switched off.

As per IEC 60831 (MPP capacitors) and IEC 60931 (APP capacitors) the capacitor should discharge to 75 V or below within 3 min as soon as the capacitor is switched off. This is to protect human beings from the risk of electric shock and also for safe re- switching of the same capacitor in APFC panel. As a general practice, discharge resistors bring the voltage to below 50 V in 1 min, which is safer.

Cylindrical capacitor's terminal block with discharge resistor

If the capacitor is re-switched without discharging sufficiently, there is a possibility that the voltage difference across the contactor may shoot up to 1000 V. More over, this results in very high peak inrush current as the rate of change of voltage is very high (I_C = C dV/dt). Such frequent switchings reduce the life of the capacitor and/or the contactor, and may cause premature failures. Hence while re-switching the capacitor (either in manual mode or auto mode) it is mandatory to discharge the capacitor to its 10% of the rated voltage.

In order to ensure the sufficient discharge, it should be ensured that the capacitor is re-switched only after 45 to 60 seconds. This time delay (for re-switching the same capacitor bank) can be set in APFC relay. In case, any application demands frequent switching of capacitors by contactors, time delay can be reduced by faster discharge of the residual voltage. Faster discharging can be achieved by replacing the existing resistors with new resistors of lesser resistance.

Formula to calculate the resistance is:

Where,

R = Discharge resistance value in Ω

t = Time for discharge from √peak voltage) to Vr (50 V), in seconds C = Rated capacitance per phase, in µF

V_n = Rated voltage of capacitor unit, in V

V_r = Permissible residual voltage, in V

The above formula is valid for resistors assembly in the delta connected capacitor (two resistors between three terminals), as shown in the figure.

However, opting for lower resistance for faster discharge will increase the power loss. At the same time, appropriate power rating (wattage) of the resistor should be chosen to ensure sufficient current carrying capacity of the resistor.

Power rating of the resistor (in watts) = 1.3*Vn*I = 1.3*V_n²/R

Here, the resistor should withstand the initial peak discharge current even if the capacitor is switched off at the instant of 30% over voltage.

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About the Author

Abhinav L Purkar,

Manager Product Management & Marketing (PMM)

Abhinav Purkar is a Product Management, Marketing, and Application Engineering professional with over 10 years of experience in the Power Quality domain. He has extensive expertise in power quality analysis, harmonic mitigation, reactive power compensation, energy efficiency, and electrical system optimization, helping customers improve system reliability and operational performance. With proven experience in product lifecycle management, market development, portfolio growth, and go-to-market strategy, Abhinav has successfully driven initiatives that enhance customer value and strengthen market presence. His strong technical foundation, combined with strategic business acumen, enables him to bridge the gap between customer requirements and innovative product offerings.