How do you calculate the size of fuse for a transformer?
Table of Contents
- 1 How do you calculate the size of fuse for a transformer?
- 2 What size breaker do I need for a 75 kva transformer?
- 3 Which fuse is used in transformers?
- 4 How do you measure a breaker for a 3 phase transformer?
- 5 How do you size a 3 phase transformer?
- 6 How do you size A 3 phase transformer?
- 7 How do you size a fuse?
- 8 Do you need to fuse the secondary of a transformer?
- 9 What is the kVA rating of a single phase transformer?
- 10 What voltage is the secondary side of a single phase transformer?
How do you calculate the size of fuse for a transformer?
4.35*250% = 10.88 amps. You can then round to the next fuse size which would be 15 Amps. Secondary Amps = VA/Secondary VAC = 2000/120 = 16.67 amps….
| Transformer primary current (amps) | Maximum overcurrent protection % |
|---|---|
| 9 amps or more | 125% |
| 2-8.99 amps | 167% |
| Less than 2 amps | 500% |
What size breaker do I need for a 75 kva transformer?
125 Amp
The rated current of the transformer can be used as the basis for a breaker. The rated current of a 3 phase, 75 kva transformer is 112 Amps, which is 25% of the rated current of a 125 Amp breaker.
How many amps is a 75 kva transformer?
208.2 Amperes
75 KVA is equal to 75,000 VA. (K= 1,000) The full value in VA, 75,000 divided by 1.732 = 43,302, which is then divided by the Voltage 208V = 208.2 Amperes. This is a “Three Step Division”, technique: VA / 1.732 / Voltage = Amperage.
Which fuse is used in transformers?
ABB WBP Transformer Fuses – Fuse Ratings & Dimensions
| Catalogue Number | Fuse Name | Rated Voltage U (kV) |
|---|---|---|
| 1YMB750747M2201 | WBP-6 | 7.2 |
| 1YMB751206M2201 | WBP-10 | 12 |
| 1YMB752405M3201 | WBP-20 | 24 |
| 1YMB753604M3201 | WBP-30 | 36 |
How do you measure a breaker for a 3 phase transformer?
Iprimary = (20 x 1000)/480 = 20,000/480 = 41.6 amps. Note: If you had a 3-phase transformer, the formula would be Iprimary = KVA x 1000/(Vprimary x 1.732). The 1.732 accounts for the 3-phase configuration. Find the circuit breaker size for the primary side of the transformer by multiplying Iprimary by 1.25.
How do you calculate current in a 3 phase transformer?
the following figure presents a nameplate of a three phase transformer….Using the aforementioned formula, let’s confirm this rating:
- Primary Voltages or High Voltages (H.V) is 11000 volts.
- Primary Current (current on High Voltage side) is 5.25 amps.
- KVA = (√3. V x I) /1000= (1.732 × 11000 × 5.25)/1000=100 KVA.
How do you size a 3 phase transformer?
the following figure presents a nameplate of a three phase transformer. It’s rating is 100 KVA….Example:
- Primary Voltages or High Voltages (H.V) is 11000 volts.
- Primary Current (current on High Voltage side) is 5.25 amps.
- KVA = (√3. V x I) /1000= (1.732 × 11000 × 5.25)/1000=100 KVA.
How do you size A 3 phase transformer?
What is the current of A 75 kVA 480 V three-phase transformer?
Three Phase Transformer
| KVA | 208V | 480V |
|---|---|---|
| 45 | 125 | 54.2 |
| 50 | 139 | 60.2 |
| 60 | 167 | 72.3 |
| 75 | 208 | 90.3 |
How do you size a fuse?
Find the size of fuse by multiplying the amps required by the device (2) by 1.5. 2×1.25 = 2.5 then we will round up to the nearest fuse size (in multiples of 5 amps) which would call for a 5 amp fuse. Cross Reference that fuse size to verify that it’s below the Maximum fuse size called out by this chart.
Do you need to fuse the secondary of a transformer?
If secondary (600V or less) fuses are sized not greater than 125% of trans- former secondary current, individual transformer fuses are not required in the primary (600V or less) provided the primary feeder fuses are not larger than 250% of the transformer rated primary current.
What type of transformer is 208208v?
208V Delta primary (input) x 208 secondary (output). 3 phase, 50hz and 60hz available, dry type open and enclosed (Nema 1 – Rated for indoor use) available. Dry type distribution transformer.
What is the kVA rating of a single phase transformer?
Single Phase Transformers. Primary Voltage Main Breaker kVA Rating Primary Lugs Secondary Lugs 208V 80A 15 100A 100A 208V 150A 25 250A 250A 208V 200A 37.5 250A 250A 208V 225A 50 400A 400A 240V 80A 15 100A 100A 240V 150A 25 250A 250A 240V 200A 37.5 250A 250A 240V 225A 50 400A 400A. Three Phase Transformers.
What voltage is the secondary side of a single phase transformer?
Primary side at 240 volts three phase (this is a rare voltage these days as most utility companies are moving to wye three phase four wire connections). The secondary side of the transformer will be 208 volts. KVA size the transformer to the secondary side load current. What is the mutual coupling in single phase transformer?
How do you calculate the voltage of a 3 phase transformer?
To check your answer (W (or VA) = V x A) multiply the primary current times the primary voltage and the secondary current times the secondary voltage and they should both equal the transformer’s kVA. Can you convert 240V 3 phase to 208V 3 phase?