OLTC / DETC
for Power Transformers
OLTC / OCTC for Power Transformers
On-load and De-Energized Tap-Changers for Power Transformers
- V TYPE
- V-VAC
- M TYPE
- D TYPE
- OC-Series
V TYPE
Current rating up to 500 A & Voltage up to 132 kV (Y/D).
Special designs are avilable for 250 and 400 A on request.
Both star and delta applications are available.
Step voltage is 1500 Volts.
In-built selector switch model.
Bi-directional power flow.
Very compact dimensional arrangement.
Easy removal of diverter switch inserts, making it maintenance friendly.
Linear version is available up to 14 positions.
Up to 27 positions are available with the pre-selector arrangement.
No barrier board problems.
Electrical parameters | ||||||||
TYPE | Current Rating (A) | Voltage Variants | BIL kV/kVp | Max. Rated Step Voltage (Volts) | Max. Operating Position | |||
Three Pole | Single Pole | Voltage Level (kV) | Vector | Linear | Pre-Selector | |||
V TYPE | 200, 350 & 500 | 350 & 700A* | 40 | Y, D | 70/200 | 1500 | 14 & 18 | 27 |
76 | 140/350 | |||||||
123/76 | 230/550 | |||||||
Matching Products
Motor Drive Unit
M TYPE
MODERN, SUPERIOR & VERSATILE
Used in up to 765 kV Transformers
Three-pole design for neutral application at 350A, 500A & 600A rating for three-phase Y-connected windings.
Single-pole design at 350A, 500A, 600A, 800A, 1200A, 1500A and 1800A ratings for auto connected windings or single-phase transformers.
Available with ±9, ±11, ±13, ±15, ±17 steps.
Special design available with 700 A, 3 Phase & 2100 & 2400 A, Single Phase*
Available on both star and delta-insulation to ground, and tap selector size can be selected independently of one another.
Convenient for bell-type tank installations.
Additional device for potential tie-in of tap winding, during change-over operation of the change-over selector.
High-speed transition resistor-type diverter switch with arc extinction at first current zero.
Diverter switch uses sharp-action mechanics by energy accumulator mounted directly on diverter switch.
Minimum possible tap selector dimension because four avilable sizes ensure matched inpulse voltage withstandability.
Radial dimensions of the tap selector are reduced by special shaping of all parts on high potential. Distances between tap selector bars determined by actual voltage stress.
Optimised integration of the change-over selector into the fine selector contact circle.
Long life and reduced maintenance - rapid tap change operation. Low thermal stress on the transition resistors.
Special contacts for alternative oil application.
<span data-metadata=""><span data-buffer="">Simple tap selector design, effective contact cooling,
high short-circuit withstandability.
Optimised integration of the change-over selector into the fine selector contact circle.
Long life and reduced maintenance - rapid tap change operation. Low thermal stress on the transition resistors.
Special contacts for alternative insulating liquids on request
<span data-metadata=""><span data-buffer="">Simple tap selector design, effective contact cooling,
high short-circuit withstandability.
Electrical parameters | ||||||||
TYPE | Current Rating (A) | Voltage Variants | BIL kV/kVp | Max. Rated Step Voltage (Volts) | Max. Operating Position | |||
Three Pole | Single Pole | Voltage Level (kV) | Vector | Linear | Pre-Selector | |||
M TYPE | 350, 500, 600 & 700* | 350, 500, 600, 800, 1200, 1500, 1800, 2100* & 2400* | 72.5 | Y, D | 140/350 | 3300 | 22 | 35 |
123 | Y, D | 230/550 | ||||||
170 | Y | 325/750 | ||||||
245 | Y | 395/950 | ||||||
300 | Y | 460/1050 | ||||||
Matching Products
Motor Drive Unit
D TYPE
Type ‘D’ Model is a true testimony of EMR’s time tested credentials for superior tap changer technology. This model is in successful service since 1975 catering to normal network applications and to demanding heavy duty furnace applications.
Current rating up to 500 A with 3-pole & up to 1500 A* with 1 pole.
Linear version applicable up to 18 position.
Special design is available for 300 A.
Voltage class up to 220 kV Class.
Both star and delta applications are available.
Maximum step voltage up to 2500 Volts.
Separate diverter and selector model.
Bi-directional power flow.
Up to 35 positions available for pre-selector arrangements.
Over 1500 in-tank installation in ultra heavy duty applications which involve 500 operations per day.
Electrical parameters | ||||||||
TYPE | Current Rating (A) | Voltage Variants | BIL kV/kVp | Max. Rated Step Voltage (Volts) | Max. Operating Position | |||
Three Pole | Single Pole | Voltage Level (kV) | Vector | Linear | Pre-Selector | |||
D TYPE | 200, 400 & 500 | 200, 400, 600*, 800*, 1200* & 1500* | 36 | Y, D | 75/200 | 2500 | 18 | 35 |
60 | 140/350 | |||||||
110 | 230/550 | |||||||
150 | 325/750 | |||||||
Matching Products
Motor Drive Unit
SERIES- OC (FOR POWER TRANSFORMERS)
| Voltage Class | Upto 145kV |
| Current Rating | Upto 650Amps |
| Step Voltage | Max.3300V |
| No.Of Taps | 05 |
| No.Of Phase/Deck | 01 / 03 |
| Connection | Selector Type |
| Operation | Manual |
| Mounting | Vertical Mounting |
| Cooling Medium | Transformer Oil |
| Voltage Class | 300kV |
| Current Rating | Upto 800Amps |
| Step Voltage | Max.7200V |
| No.Of Taps | 05 |
| No.Of Phase/Deck | 03 |
| Connection | Bridge Type |
| Operation | Manual |
| Mounting | Gear Mounting |
| Cooling Medium | Transformer Oil |
| Voltage Class | 170 / 300kV |
| Current Rating | 500 / 800Amps |
| Step Voltage | Max.11kV |
| No.Of Taps | 06 |
| No.Of Phase/Deck | 01 / 03 |
| Connection | Linear |
| Operation | Motorized |
| Mounting | Vertical Mounting |
| Cooling Medium | Transformer Oil |
| Voltage Class | 300kV |
| Current Rating | Upto 800Amps |
| Step Voltage | Max.11kV |
| No.Of Taps | 07 |
| No.Of Phase/Deck | 03 |
| Connection | Change Over Selector |
| Operation | Motorized |
| Mounting | Vertical Mounting |
| Cooling Medium | Transformer Oil |
Power Transformers - frequently asked questions
What does an OLTC do in transmission-class power transformers?
Why do Utilities Specify OLTC-equipped power transformers in grid expansion projects?
How does vacuum-based OLTC switching improve service life in power transformers?
Which OLTC configurations are selected for different transmission transformer duty requirements?
When is OCTC preferred over OLTC in high-voltage transformer procurement?
*on request, please contact us
We provide a wide range of spares and accessories for your mission critical equipments. We are committed to provide best customer services to ensure smooth operations at all times
Our Clients
