When a Missequenced Start Costs More Than a Relay
Consider a compressor station where three motors must start in a defined sequence — each with a minimum inter-start delay — to prevent simultaneous inrush current from collapsing the busbar voltage. If those delays are managed by mechanical timers or fixed-time auxiliary relays, one calibration drift or contact weld is enough to slam all three motors online together. The resulting voltage dip trips protective relays, shuts down the station, and demands a full restart procedure that can keep the line idle for hours. In oil, gas, and petrochemical facilities, where process continuity and personnel safety are non-negotiable, that scenario is not a theoretical risk — it is a documented failure mode.
Programmable multifunction time delay relays — specifically the Novatek Electro REV-120, REV-114, and REV-201M — are the panel-design answer to this problem. Each device is microprocessor-based, DIN-rail mountable, and field-configurable to cover the timing functions that recur across petrochemical automation panels: on-delay, off-delay, cyclic, pulse, and star-delta sequencing.
Why Timing Precision Is a Safety and Reliability Requirement in Oil, Gas & Petrochemical
Upstream, midstream, and downstream hydrocarbon facilities share a common characteristic: process equipment starts, stops, and transitions in interlocked sequences where timing errors propagate rapidly into safety events. Several engineering realities drive this:
- High-inertia motor loads: Compressors, pumps, and blower fans in gas processing plants carry substantial rotating mass. Star-delta starting reduces DOL inrush from 6–8× FLA to approximately 2–3× FLA — but only if the transition delay is correctly timed. Too short, and the motor is switched to delta before it reaches sufficient speed, recreating the inrush spike. Too long, and the star contactor overheats.
- Sequential process interlocks: Crude distillation units, gas sweetening trains, and LPG bottling lines depend on equipment starting in prescribed order — cooling water before fired heaters, seal-gas compressors before main compressors, purge blowers before ignition circuits. Each inter-stage delay must be repeatable to the second across thousands of operating cycles.
- HVAC and ventilation safety: Classified hazardous areas (Zone 1, Zone 2 per IEC 60079) require forced-ventilation systems to pre-purge enclosures for a defined interval before electrical equipment can be energised. A programmable cyclic or on-delay timer provides that verifiable, repeatable delay.
- Instrument air and utility systems: Compressor drain valves, dewpoint analyzers, and regenerative drier cycles all rely on timed open/close sequences. Fixed mechanical timers drift with temperature and vibration — a common condition in outdoor petrochemical installations across India's climate range.
Applicable Standards for Timing and Control in Petrochemical Panels
Panel builders and instrumentation engineers working in Indian oil, gas, and petrochemical projects reference the following standards when specifying timing relays:
- IS/IEC 61812-1: Time relays for industrial and residential use — defines accuracy classes, operating modes, and test methods directly applicable to REV-series devices.
- IS/IEC 60947-5-1: Low-voltage switchgear and controlgear — control circuit devices and switching elements, covering the SPDT relay contacts rated at 6 A in these models.
- IEC 60079-14: Electrical installations design, selection, and erection in explosive atmospheres — specifies ventilation pre-purge timing requirements met by programmable on-delay functions.
- IS 13947 (Parts 1–5): Indian counterpart to IEC 60947 for low-voltage switchgear, commonly cited in OISD and PESO documentation packages.
- OISD-STD-137 / OISD-STD-144: Oil Industry Safety Directorate standards covering electrical installations and safety systems in petroleum facilities, which mandate reliable, verifiable sequencing for motor control.
The Novatek REV Series: Three Models, One Unified Platform Philosophy
All three relays share a common form factor — 35 mm DIN-rail mount, 220–240 V AC (50/60 Hz) supply, 6 A SPDT output contact, and a time range spanning 0.1 seconds to 10 days across 10 selectable ranges. What differentiates them is the breadth of operating modes and display/control features. Below is the comparative specification table:
| Parameter | REV-120 | REV-114 | REV-201M |
|---|---|---|---|
| Supply Voltage | 220–240 V AC, 50/60 Hz | 220–240 V AC, 50/60 Hz | 220–240 V AC, 50/60 Hz |
| Output Contact | SPDT (2NO+2NC), 6 A | SPDT (2NO+2NC), 6 A | SPDT, 6 A |
| Time Range | 0.1 sec – 10 days, 10 ranges | 0.1 sec – 10 days, 10 ranges | 0.1 sec – 10 days, 10 ranges |
| Operating Modes | 10 modes incl. star-delta | 17 modes | Multiple modes |
| Star-Delta Mode | Yes (dedicated mode) | No | Yes |
| Digital Display | Yes | Yes | Yes |
| External Input | Yes | Yes | Yes |
| MRP (ex-GST) | Rs. 1,900 | Rs. 2,050 | Rs. 2,833 |
All prices are ex-GST. GST at 18% is applicable additionally. Prices effective from 01.04.2026 as per Novatek Electro Price List 2026-27.
REV-120: The Star-Delta Specialist for Motor Control in Process Plants
The REV-120 is a microprocessor-based device offering ten operating modes, with dedicated star-delta timing as a headline function. In oil and gas applications, the REV-120 is particularly suited to:
- Motor star-delta starting circuits for centrifugal pumps and compressors: The dedicated star-delta mode controls the transition timing between star and delta contactors — typically set between 5 and 15 seconds depending on motor inertia — eliminating the need for a separate star-delta timer relay and reducing panel wiring complexity.
- Conveyor sequencing on product-transfer systems: In LPG cylinder filling lines or bulk liquid loading gantries, belt conveyors must start in reverse sequence (downstream first, then upstream) to prevent product accumulation. The REV-120's on-delay and cyclic modes allow this staging to be programmed and reliably repeated.
- Process delay control in gas sweetening or dehydration units: Where a downstream valve or exchanger must be conditioned before an upstream flow starts, the REV-120's on-delay mode enforces the hold-off interval to the second.
Price: Rs. 1,900 per piece (ex-GST)
Buy REV-120 OnlineREV-114: Maximum Mode Flexibility for Complex Interlock Logic
The REV-114 offers the widest operating-mode library in the REV series — seventeen programmable algorithms — including on-delay, off-delay, periodic with on-delay, periodic with time delay when energising, and pulse modes. Its digital display and control buttons make field adjustment straightforward without opening the panel or accessing a laptop.
For petrochemical panel builders, the REV-114 addresses:
- HVAC and forced-ventilation pre-purge timing in classified areas: Zone 1 and Zone 2 enclosures require a defined air-change pre-purge interval before power-up. The REV-114's on-delay mode, set to the calculated purge time, provides this function with a lockout contact that prevents energisation until the timer completes.
- Irrigation and utility water timing for cooling towers and firewater systems: Scheduled fill cycles for cooling tower make-up water or sprinkler system test sequences benefit from the REV-114's cyclic modes, which allow independent on-time and off-time programming.
- Instrument air drier regeneration cycles: Heatless desiccant driers switch between towers on a timed cycle. The REV-114's periodic modes can drive the switching sequence directly, with the external input accepting a dewpoint transmitter signal to override the cycle if needed.
Price: Rs. 2,050 per piece (ex-GST)
Buy REV-114 OnlineREV-201M: The High-Feature Relay for Demanding Automation Panels
The REV-201M combines the star-delta capability of the REV-120 with an expanded feature set and enhanced programmability, making it the preferred choice for complex automation panels where a single relay must cover multiple potential timing scenarios across a panel's operational life.
In oil, gas, and petrochemical applications, the REV-201M is suited to:
- Multi-motor sequential start panels for pump stations: Where three or more motors must start with defined inter-start delays, a REV-201M per motor provides independent, programmable delay with visual status confirmation via its display — critical for maintenance personnel who need to verify sequence status without interpreting indicator lamp logic.
- Flare system blower and pilot flame sequencing: Flare control panels require blower pre-purge, pilot ignition delay, and main flame confirmation steps — all timed. The REV-201M's multiple modes in a single device reduce the relay count and potential failure points in the panel.
- SCADA-integrated panels where external input triggers timing: The external input terminal accepts a dry contact from a DCS or SCADA digital output, allowing the timing relay to be triggered remotely while executing its locally programmed time sequence — a practical hybrid for facilities that have centralised control but retain hard-wired safety interlocks.
Price: Rs. 2,833 per piece (ex-GST)
Buy REV-201M OnlineQuick Selection Guide
| Application Type | Recommended Model | Key Mode Used | Price (ex-GST) |
|---|---|---|---|
| Motor star-delta starting (pumps, compressors) | REV-120 | Star-Delta Timer | Rs. 1,900 |
| Conveyor start-stop sequencing | REV-120 / REV-201M | On-Delay, Cyclic | Rs. 1,900 / Rs. 2,833 |
| HVAC pre-purge in classified areas | REV-114 | On-Delay | Rs. 2,050 |
| Instrument air drier regeneration cycles | REV-114 | Cyclic / Periodic | Rs. 2,050 |
| Multi-motor sequential start panels | REV-201M | On-Delay, Star-Delta | Rs. 2,833 |
| Process delay (valve sequencing, flow conditioning) | REV-120 / REV-114 | On-Delay, Off-Delay | Rs. 1,900 / Rs. 2,050 |
| Flare system blower and ignition sequencing | REV-201M | On-Delay, Pulse | Rs. 2,833 |
| Irrigation / cooling tower utility timing | REV-114 | Cyclic Timer | Rs. 2,050 |
Why Novatek Electro?
- ISO 9001:2015 Certified Manufacturing: Every REV-series relay is produced under a documented quality management system, ensuring consistent performance across production batches — critical when you are specifying the same model across a 20-panel EPC project.
- CE Marked for International Project Compliance: Facilities under international joint-venture ownership or EPC contracts with European or multinational project specifications can include REV-series relays without additional conformity documentation hurdles.
- Made in India — Delhi-Based Manufacturer: Domestic manufacturing means shorter lead times, availability of spares, and direct technical support without import delay or foreign currency exposure.
- 30+ Years of Product Development in Electrical Protection: Novatek Electro has been engineering protective and control relays for Indian industrial conditions — wide ambient temperature range, dust, vibration, and utility-grade power quality — for over three decades.
- Dedicated After-Sales and Technical Support: Panel builders and instrumentation contractors can access technical documentation, wiring diagrams, and programming guidance through Novatek Electro's technical team and authorised distribution network across India.
Ready to Specify REV-Series Relays in Your Next Panel?
Whether you are designing a motor control centre for a gas processing plant, a conveyor sequencing panel for a loading terminal, or an HVAC interlock panel for a classified-area substation — the REV-120, REV-114, and REV-201M cover your timing requirements from Rs. 1,900 per relay (ex-GST).
Shop REV Series on Intelli-Electro Email: sales@novatek-electro.in
Call / WhatsApp: +91-7840054744
Frequently Asked Questions
Q: Which model should I choose if I only need star-delta timing for a single motor starter panel?
A: The REV-120 at Rs. 1,900 (ex-GST) is the most cost-effective choice. It has a dedicated star-delta timing mode among its ten operating modes, a 6 A SPDT output contact rated for direct contactor coil control, and an external input for PLC or pushbutton triggering. If your panel needs to handle multiple timing scenarios in its operational life, consider the REV-201M, which includes star-delta mode alongside a broader feature set.
Q: What is the timing accuracy of these relays, and how does it compare to mechanical cam timers?
A: All three REV-series relays are microprocessor-based, which means timing is derived from a crystal-controlled internal clock rather than mechanical spring tension or motor-driven cams. Microprocessor timers maintain their set-point accuracy over temperature variation and operational cycles, whereas mechanical timers drift with wear, temperature, and vibration — conditions common in outdoor petrochemical installations. For applications requiring repeatable delays to the second across thousands of cycles, the digital REV-series is the appropriate choice.
Q: Can the external input on the REV-120 and REV-114 accept a signal directly from a PLC digital output?
A: Yes. The external input terminals accept a dry-contact or voltage signal and can be wired directly to a PLC digital output module or a relay output from a DCS. This allows the timing relay to be triggered by an automated sequence controller while executing its locally programmed delay — a common hybrid architecture in petrochemical facilities that retain hard-wired safety interlocks alongside PLC-based sequencing.
Q: What is the minimum and maximum time range available, and can I change the range in the field?
A: All three models provide a time range from 0.1 seconds to 10 days, selectable across 10 programmable ranges. The range is selectable via front-panel buttons without opening the device or accessing any internal components, making field adjustment straightforward during commissioning or when process timing requirements change.
Q: Are these relays suitable for installation in panels located in humid or dusty petrochemical environments?
A: The REV-series relays are DIN-rail mounted devices designed for installation inside an IP-rated enclosure, which is standard practice in petrochemical panels. The devices themselves are microprocessor-based and sealed against typical panel interior conditions. For outdoor or classified-area installations, the panel enclosure must be rated to the appropriate IP and ATEX/IECEx classification — the relay inside benefits from that protection. Always consult the product datasheet for specific environmental ratings.
Q: How many operating modes does the REV-114 have, and why does it have more than the REV-120?
A: The REV-114 offers seventeen operating algorithms, including multiple variants of on-delay, off-delay, periodic, and pulse modes. The REV-120 has ten modes, with the addition of a dedicated star-delta mode not present on the REV-114. The REV-114 is designed for applications requiring the widest possible mode flexibility — such as complex interlock logic, multi-step process sequences, or panels where the exact timing function may be defined after panel assembly. The REV-120 trades some mode breadth for star-delta capability.
Q: What is the contact rating of the output relay, and can it drive a standard 230 V AC contactor coil directly?
A: The output contact on all three models is rated at 6 A, SPDT (2NO+2NC). Standard 230 V AC contactor coils for motor starters in the 11–22 kW range draw 0.1 to 0.5 A — well within the 6 A contact rating. For larger contactors with higher coil inrush, or where the relay drives multiple parallel loads, verify the total coil current does not exceed the 6 A contact rating. An intermediate relay may be required for high-inrush or multiple-coil applications.
Q: Is the REV-201M significantly different from the REV-120, or is it simply a higher-priced version of the same device?
A: The REV-201M shares the star-delta timing capability of the REV-120 but includes an expanded operating mode set, enhanced display functionality, and additional programmability suited to more complex automation panels. At Rs. 2,833 (ex-GST) versus Rs. 1,900 for the REV-120, the REV-201M is appropriate for panels where a single relay must cover diverse timing scenarios across the panel's life, or where maintenance personnel need clearer operational feedback from the display. For straightforward star-delta applications, the REV-120 remains the cost-optimised choice.
Q: Do these relays comply with any Indian or international standards that can be cited in an EPC project specification?
A: The REV-series relays are CE marked, indicating conformity with applicable European directives including the Low Voltage Directive. They are manufactured by an ISO 9001:2015 certified facility. For Indian project documentation, reference IS/IEC 61812-1 (time relays) and IS/IEC 60947-5-1 (control circuit switching elements). The CE mark and ISO 9001:2015 certification are typically acceptable in EPC project quality submissions, though project-specific requirements should be verified against the relevant vendor qualification criteria.
Q: Can I use a cyclic mode on the REV-114 for alternating two pumps on a timed duty-standby cycle?
A: The REV-114's cyclic modes allow independent on-time and off-time programming. For a simple alternating pump cycle where Pump A runs for a set period and then Pump B takes over, the cyclic output of the REV-114 can drive an intermediate relay or contactor changeover circuit. For applications requiring true duty-standby alternation with flow-sensing override, a dedicated pump alternator relay (such as Novatek Electro's motor protection series) may be more appropriate, but the REV-114 cyclic mode serves well for fixed-interval utility cycling without process feedback.
Q: What happens to the timer state if supply power is interrupted during a timing cycle?
A: Microprocessor-based timers without battery-backed NVRAM will reset their timing cycle on power restoration, restarting from time zero. For applications where power interruption must not cause a dangerous sequence restart — such as a mid-cycle star-delta transition — the panel design should include appropriate interlocks (e.g., motor speed detection or a delayed restart contactor) to ensure the sequence restarts safely from a known state. Consult the specific model datasheet for power-failure behaviour details.
Q: Where can I purchase the REV-120, REV-114, and REV-201M, and what is the typical delivery timeline?
A: All three models are available for purchase through the authorised online store at https://intelli-electro.com. For bulk orders, project quantities, or distributor pricing, contact the Novatek Electro sales team at sales@novatek-electro.in or call +91-7840054744. As a Delhi-based Indian manufacturer, standard stocking items typically have shorter lead times than imported alternatives.
Q: Is GST included in the listed prices, and are there volume discount options for project purchases?
A: The listed prices — Rs. 1,900 for REV-120, Rs. 2,050 for REV-114, and Rs. 2,833 for REV-201M — are all exclusive of GST. GST at 18% is applicable additionally as per current tax regulations. For project-quantity pricing, OEM agreements, or panel-builder terms, contact sales@novatek-electro.in directly with your requirement and project details.
Q: Can these relays be used in a 60 Hz power system, such as in facilities with imported equipment or generator sets configured for 60 Hz?
A: Yes. All three REV-series relays are rated for 220–240 V AC at 50/60 Hz, making them compatible with both the standard Indian 50 Hz grid supply and 60 Hz generator or UPS systems used in some process plant configurations. The microprocessor-based timing circuit is not dependent on the supply frequency for its timing accuracy, so the set delay values remain consistent regardless of whether the supply is 50 Hz or 60 Hz.
